That many Roman Catholics, past and present, are true Christians, is a palpable fact. It is a fact which no man can deny without committing a great sin. It is a sin against Christ not to acknowledge as true Christians those who bear his image, and whom He recognizes as his brethren. It is a sin also against ourselves. We are not born of God unless we love the children of God. If we hate and denounce those whom Christ loves as members of his own body, what are we? It is best to be found on the side of Christ, let what will happen. It is perfectly consistent, then, for a man to denounce the papacy as the man of sin, and yet rejoice in believing, and in openly acknowledging, that there are, and ever have been, many Romanists who are the true children of God.
That Romanists as a society profess the true religion, meaning thereby the essential doctrines of the gospel, those doctrines which if truly believed will save the soul, is, as we think, plain. . . . If this creed were submitted to any intelligent Christian without his knowing whence it came, could he hesitate to say that it was the creed of a Christian church? Could he deny that these are the very terms in which for ages the general faith of Christendom has been expressed? Could he, without renouncing the Bible, say that the sincere belief of these doctrines would not secure eternal life? Can any man take it upon himself in the sight of God, to assert there is not truth enough in the above summary to save the soul? If not, then a society professing that creed professes the true religion in the sense stated above.
As I mentioned here, Charles Hodge, while being a great critic of the Catholic Church and Catholic doctrine, held that the Catholic Church is a part of the visible church of Christ. In order to further illustrate Hodge's view of "Romanists" as Christians, I am collecting here a series of quotations which show Hodge's attitude. You can see in these quotations both Hodge's antipathy to Catholicism as well as his recognition that the Catholic Church is part of the visible church of Christ and that there are brothers and sisters in Christ within it. May Hodge's ability to be nuanced and careful and charitable in his approach to "Romanists" be a model to all of us in our dealings with those with whom we disagree.
This is just a sampling after about a half-an-hour of research. There is, of course, much more out there that Hodge has said about "Romanists." I'll continue to add quotations as I come across them in the future. Keep in mind that many of these quotations are somewhat "by the way" in that they occur in the context of Hodge's discussion of other subjects. See the links to find the larger context of each quotation. Also, keep in mind that I do not, of course, necessarily agree with many of Hodge's characterizations of Catholic doctrine or his criticisms of Catholic doctrine. But this is not the place to refute his errors in this regard.
The true method in theology requires that the facts of religious experience should be accepted as facts, and when duly authenticated by Scripture, be allowed to interpret the doctrinal statements of the Word of God. So legitimate and powerful is this inward teaching of the Spirit, that it is no uncommon thing to find men having two theologies, -- one of the intellect, and another of the heart. The one may find expression in creeds and systems of divinity, the other in their prayers and hymns. It would be safe for a man to resolve to admit into his theology nothing which is not sustained by the devotional writings of true Christians of every denomination. It would be easy to construct from such writings, received and sanctioned by Romanists, Lutherans, Reformed, and Remonstrants, a system of Pauline or Augustinian theology, such as would satisfy any intelligent and devout Calvinist in the world. (Systematic Theology, Vol. I (Grand Rapids, MI: Eerdmans, 1940), pp. 16-17 [in the Hendrickson 2003 reprint], taken from the plain text version on the website of the Christian Classics Ethereal Library.)
The first remark which suggests itself on the comparison of these several schemes is, that the relation between the believer and Christ is far more close, peculiar, and constant on the Protestant scheme than on any other. He is dependent on Him every hour; for the imputation of his righteousness; for the supplies of the Spirit of life; and for his care, guidance, and intercession. He must look to Him continually; and continually exercise faith in Him as an ever present Saviour in order to live. According to the other schemes, Christ has merely made the salvation of all men possible. There his work ended. According to Romanists, He has made it possible that God should give sanctifying grace in baptism; according to the Remonstrants, He has rendered it possible for Him to give sufficient grace to all men whereby to sanctify and save themselves. We are well aware that this is theory; that the true people of God, whether Romanists or Remonstrants, do not look on Christ thus as a Saviour afar off. They doubtless have the same exercises towards Him that their fellow believers have; nevertheless, such is the theory. The theory places a great gulf between the soul and Christ. (Systematic Theology, Vol. III (Grand Rapids, MI: Eerdmans, 1940), pp. 193-194 [in the Hendrickson 2003 reprint], taken from the plain text version on the website of the Christian Classics Ethereal Library.)
Fourthly, the Protestant doctrine is the only one on which the soul can live. This has been urged before when speaking of the work of Christ. It is fair to appeal from theology to hymnology from the head to the heart; from what man thinks to what God makes men feel. It is enough to say on this point, that Lutheran and Reformed Christians can find nowhere, out of the Bible, more clear, definite, soul-satisfying expression of their doctrinal views upon this subject, than are to be found in many, of the hymns of the Latin and Arminian churches. (Ibid., 194-195)
As all denominations of Christians, Romanists and Protestants, are of one mind on this subject, it is matter of astonishment that these objectionable divorce laws are allowed to stand on the statute-books of so many of our states. This fact proves either that public attention has not to a sufficient degree been called to the subject, or that the public conscience is lamentably blinded or seared. The remedy is with the Church, which is the witness of God on earth, bound to testify to his truth and to uphold his law. If Christians, in their individual capacity and in their Church courts, would unite in their efforts to arouse and guide public sentiment on this subject, there is little doubt that these objectionable laws would be repealed. (Ibid., 406)
Ritualism is a broad, smooth, and easy road to heaven, and is always crowded. It was much easier in Paul's time to be a Jew outwardly than to be one inwardly; and circumcision of the flesh was a slight matter when compared to the circumcision of the heart. A theory which allows a man to be religious, without being holy; to serve both God and mammon; to gain heaven without renouncing the world, will never fail to find numerous supporters. That there is such a theory: that it has prevailed extensively and influentially in the Church; and that it is prevalent over a large part of Christendom, cannot be disputed. It does not follow, however, that all who are called ritualists, or who in fact attribute undue importance to external rites, are mere formalists. Many of them are, no doubt, not only sincere, but spiritual Christian men. This is no proof that the system is not false and evil, All Protestants cheerfully admit that many Romanists are holy men; but they no less strenuously denounce Romanism as an apostasy from the pure Gospel. (Ibid., 583)
Dr. John Henry Newman says, that if Protestants insist on making the Church of Rome Antichrist, they thereby make over all Roman Catholics, past and present, "to utter and hopeless perdition."  This does not follow. The Church of Rome is to be viewed under different aspects; as the papacy, an external organized hierarchy, with the pope, with all his arrogant claims, at its head; and also as a body of men professing certain religious doctrines. Much may be said of it in the one aspect, which is not true of it in the other. Much may be said of Russia as an empire that cannot be said of all Russians. At one time the first Napoleon was regarded by many as Antichrist; that did not involve the belief that all Frenchmen who acknowledged him as emperor, or all soldiers who followed him as their leader, were the sons of perdition. That many Roman Catholics, past and present, are true Christians, is a palpable fact. It is a fact which no man can deny without committing a great sin. It is a sin against Christ not to acknowledge as true Christians those who bear his image, and whom He recognizes as his brethren. It is a sin also against ourselves. We are not born of God unless we love the children of God. If we hate and denounce those whom Christ loves as members of his own body, what are we? It is best to be found on the side of Christ, let what will happen. It is perfectly consistent, then, for a man to denounce the papacy as the man of sin, and yet rejoice in believing, and in openly acknowledging, that there are, and ever have been, many Romanists who are the true children of God. (Ibid., 822)
The whole system, so far as it is distinctive, is a system of falsehood, or false pretensions, supported by deceit. [After the word "distinctive" in the text, there is this footnote:] This qualification is necessary. Papists of course hold the truths of natural religion; and many of the distinguishing doctrines of the Gospel. This is to be acknowledged. We are not to deny that truth is truth, because held by Romanists; nor are we to deny, that where truth is, there may be its fruits. While condemning Papacy, Protestants can, and do joyfully admit that there are among Romanists such godly men as St. Bernard, Fénélon, and Pascal, and doubtless thousands more known only unto God. (Ibid., 817)
By the Church doctrine [Hodge refers to the doctrine of the final judgment] is meant that doctrine which is held by the Church universal; by Romanists and Protestants in the West, and by the Greeks in the East. That doctrine includes the following points: (Ibid., 845)
The doctrine of Romanists on this subject [that is, the subject of works not being the ground of justification] is much higher. Romanism retains the supernatural element of Christianity throughout. Indeed it is a matter of devout thankfulness to God that underneath the numerous grievous and destructive errors of the Romish Church, the great truths of the Gospel are preserved. The Trinity, the true divinity of Christ, the true doctrine concerning his person as God and man in two distinct natures and one person forever; salvation through his blood, regeneration and sanctification through the almighty power of the Spirit, the resurrection of the body, and eternal life, are doctrines on which the people of God in that communion live, and which have produced such saintly men as St. Bernard, Fénélon, and doubtless thousands of others who are of the number of God's elect. Every true worshipper of Christ must in his heart recognize as a Christian brother, wherever he may be found, any one who loves, worships, and trusts the Lord Jesus Christ as God manifest in the flesh and the only Saviour of men. On the matter of justification the Romish theologians have marred and defaced the truth as they have almost all other doctrines pertaining to the mode in which the merits of Christ are made available to our salvation. They admit, indeed, that there is no good in fallen man; that he can merit nothing and claim nothing on the ground of anything he is or can do of himself. He is by nature dead in sin; and until made partaker of a new life by the supernatural power of the Holy Ghost, he can do nothing but sin. For Christ's sake, and only through his merits, as a matter of grace, this new life is imparted to the soul in regeneration (i.e., as Romanists teach, in baptism). As life expels death; as light banishes darkness, so the entrance of this new divine life into the soul expels sin (i.e., sinful habits), and brings forth the fruits of righteousness. Works done after regeneration have real merit, "meritum condigni," and are the ground of the second justification the first justification consisting in making the soul inherently just by the infusion of righteousness. According to this view, we are not justified by works done before regeneration, but we are justified for gracious works, i.e., for works which spring from the principle of divine life infused into the heart. The whole ground of our acceptance with God is thus made to be what we are and what we do. (Ibid., 135-136)
There is a fourth established meaning of the word church, which has more direct reference to the question before us. It often means an organized society professing the true religion, united for the purpose of worship and discipline, and subject to the same form of government and to some common tribunal. . . .
All we contend for is that the church is the body of Christ, that those in whom the Holy Spirit dwells are members of that body; and consequently that whenever we have evidence of the presence of the Spirit, there we have evidence of the presence of the church. And if these evidences occur in a society professing certain doctrines by which men are thus born unto God, it is God’s own testimony that such society is still a part of the visible church. It strikes us as one of the greatest absurdities of Ritualism, whether among Romanists or Anglicans, that it sets up a definition of the church, not at all commensurate with its actual and obvious extent. What more glaring absurdity can be uttered than that the Episcopal church in this country is here the only church, when nine tenths of the true religion of the country exists without its pale. It may be man’s church, but God’s church is much wider. Wherever, therefore, there is a society professing truth, by which men are actually born unto God, that society is within the definition of the church given in our standards, and if as a society, it is united under one tribunal for church purposes, it is itself a church.
The next step in the argument is, of course, the consideration of the question, whether the church of Rome comes within the definition, the correctness of which we have endeavored to establish? It was very common with the reformers and their successors to distinguish between the papacy, and the body of people professing Christianity under its dominion. When, by the church of Rome they meant the papacy, the denounced it as the mystical Babylon, and synagogue of Satan; when they meant by it the people, considered as a community professing the essential doctrines of the gospel, they admitted it to be a church. This distinction is natural and just, though it imposes the necessity of affirming and denying the same proposition. If by the church of Rome, you mean one thing, it is not a church; if you mean another, it is a church. People will not trouble themselves, however, with such distinctions, though they often unconsciously make them, and are forced to act upon them. Thus by the word England, we sometimes mean the country, sometimes the government, and sometimes the people. If we mean by it the government, we may say (in reference to some periods of its history), that it is unjust, cruel, persecuting, rapacious, opposed to Christ and his kingdom: when these things could not be said with truth of the people .
Though we regard the above distinction as sound, and though we can see no more real contradiction in saying Rome is a church, and is not a church, than in saying a man is mortal and yet immortal, spiritual yet carnal, a child of God yet sold under sin; yet as the distinction is not necessary for the sake either of truth or perspicuity, we do not intend to avail ourselves of it. All that we have to beg is, that brethren would not quote against us the sweeping declarations and denunciations of our Protestant fore-fathers against popery as the man of sin, antichrist, the mystical Babylon, and synagogue of Satan, as proof of our departure from the Protestant faith. In all those denunciations we could consistently join; just as our fathers, as Professor Thornwell acknowledges, while uttering those denunciations, still admitted Rome, in one sense, to be a church. Our present object is to enquire whether the church of Rome, taking the term as Bishop Sanderson says, Conjunctim pro toto aggregato, just as we take the term, church of England, falls within the definition of a church given above. . . .
That Romanists as a society profess the true religion, meaning thereby the essential doctrines of the gospel, those doctrines which if truly believed will save the soul, is, as we think, plain. 1. Because they believe the Scriptures to be the word of God. 2. They direct that the Scriptures should be understood and received as they were understood by the Christian Fathers. 3. They receive the three general creeds of the church, the Apostle’s, the Nicene, and the Athanasian, or as these are summed up in the creed of Pius V. 4. They believe in one God, the Father Almighty, maker of heaven and earth, and of all things visible and invisible. In one Lord Jesus Christ, the only-begotten Son of God, begotten of his Father before all worlds, God of God, Light of Light, very God of very God, begotten not made, being of one substance with the Father, by whom all things were made. Who for us men, and for our salvation, came down from heaven, and was incarnate by the Holy Ghost of the Virgin Mary, and was made man. And was crucified also for us under Pontius Pilate, suffered and was buried. And the third day rose again with glory to judge both the quick and the dead, whose kingdom shall have no end. And they believe in one catholic apostolic church. They acknowledge one baptism for the remission of sins, and look for the resurrection of the dead and the life of the world to come.
If this creed were submitted to any intelligent Christian without his knowing whence it came, could he hesitate to say that it was the creed of a Christian church? Could he deny that these are the very terms in which for ages the general faith of Christendom has been expressed? Could he, without renouncing the Bible, say that the sincere belief of these doctrines would not secure eternal life? Can any man take it upon himself in the sight of God, to assert there is not truth enough in the above summary to save the soul? If not, then a society professing that creed professes the true religion in the sense stated above. 5. We argue from the acknowledged fact that God has always had, still has, and is to have a people in that church until its final destruction; just as he had in the midst of corrupt and apostate Israel. We admit that Rome has grievously apostatized from the faith, the order and the worship of the church; that she has introduced a multitude of false doctrines, a corrupt and superstitious and even idolatrous worship, and a most oppressive and cruel government; but since as a society she still retains the profession of saving doctrines, and as in point of fact, by those doctrines men are born unto God and nurtured for heaven, we dare not deny that she is still a part of the visible church. We consider such a denial a direct contradiction of the Bible, and of the facts of God’s providence. It was within the limits of the church the great anti-christian power was to arise; it was in the church the man of sin was to exalt himself; and it was over the church he was to exercise his baneful and cruel power. (From Is the Church of Rome a Part of the Visible Church?)
Published (at least the first part) on the feast of St. Teresa of Avila.