To the substance of faith belong first of all the two articles called general, regarding the existence of God, and His providential care for man's salvation. In these two, as being the primary truths of faith, are, according to the teaching of S. Thomas,* implicitly contained all the other articles. For they are so contained, either by reason of the very nature of God, or by a positive act of His good pleasure. Thus all the articles on the Perfections of God, His Unity of Essence and Trinity of Persons are, by reason of the Divine Nature, contained in the truth of God's Existence and Being; and all the other revealed truths are, by a positive act of His good pleasure, contained in the article, that He has a providential care for man's salvation. Hence, whoever expressly believes as a truth of revelation in the existence of God, is held to believe implicitly that He is One in Essence and Three in Persons. In like manner he who expressly believes that God has a providential care for men, is held to believe implicitly in all those particular means, whereby He has of His own good pleasure decreed to lead man to salvation.
The mysteries of the Trinity, and Redemption through the Incarnate Word, are the two revealed articles called particular. These also belong to the substance of faith, though not in so strict a sense as the two general articles.
The other truths contained in the deposit of revelation are considered as accessory to the substance of faith and connected with it.
With regard to the two general articles, viz., the existence of God, and His providential care for man's salvation, which belong to the substance of faith, the common teaching of theologians is that faith in these truths was at all times from the beginning of the world precisely the same as it is now in the Christian Dispensation, and that an explicit belief of these two truths was always obligatory as a necessary means of salvation. For, since all men, from the beginning of the world, were destined for the same beatitude as ourselves, they all had necessarily to tend towards that beatitude by means of hope; but this they could not do, unless, in a true sense, they had, at least substantially, the self-same faith with us in God, and a like hope in Him, through belief in His promise of salvation.+