The topic of Article 7 deserves close attention: the objections arise under the heading videtur quod articuli fidei non creverint secundum temporum successionem. That is to say, St. Thomas is asking whether the articles of faith increased (note the past tense!) over time. He is not asking whether there is such a thing as development of doctrine, which is (present tense!) an increased understanding of the articles of faith over time. His attention is focused on the period before Christ.
Once his topic is clearly seen, the position he takes is unremarkable. God revealed more and more over time, and revelation culminated in the time of Christ and his apostles, after which point we do not await any further revelation until the second coming.
However, the arguments he uses to support his position are penetrating. At the moment I want to focus on his reply to the fourth objection. There he says that the final consummation of grace—which could include the gift of revelation—came through Christ, and from this fact he reasons that those who were closest to the time of Christ knew the mysteries of faith more fully. In the ages before Christ, the prophets who lived closer to Christ’s time knew the mysteries of faith more fully than those who lived earlier—that much seems intuitive.
But he goes on to say that, among those who lived after Christ, those who were closer to Christ’s time knew the mysteries of faith more fully than those who lived later. This may be counterintuitive, because in fact the succeeding centuries have been rich in reflection and probing ever more deeply into the mysteries. St. Thomas himself, as he writes this article, is engaged in an explication of the faith hardly imaginable without all the intervening centuries of thinkers and saints who laid the foundations for his remarkable achievement.
But I don’t think St. Thomas is saying that the Apostles and those of their generation had the most articulated and systematic grasp of the mysteries. He is not saying that their grasp of the faith was the best in a discursive way. Rather, I think he is pointing to their immediate, non-discursive, intuitive grasp of the mysteries. As brilliantly as St. Thomas wrote about the mysteries, he could never have written these lines from the First Letter of John:
That which was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon and touched with our hands, concerning the word of life—the word was made manifest, and we saw it….
All the wonderful reasoning which later thinkers would do about the mysteries rests on the Apostle’s immediate, non-reasoning contact with the mysteries themselves in the privileged time of revelation’s consummation. For theology, this is a distinction worth bearing in mind: there is a knowledge of the faith which is discursive and there is a knowledge of the faith which is a motionless gaze, and the latter is more fundamental than the former.
My experience has been that reasoning can wonderfully deepen one’s intuitive grasp of things; this is one of the chief reasons for reasoning. But grace can lift one to a deeper gaze into the mysteries than a lifetime of reasoning, as we see in the case of someone like St. Theresa of Avila. This is why thousands of years of reflection by the greatest minds of all time can be devoted simply to unpacking the short writings of the Apostles, whose only claim to erudition was that they had touched with their own hands the very Word of God.