In Paul’s letters, there are a number of places in which the literal translation would be “the faithfulness of Christ” as being front and center for our salvation. Of course our faith is factored into that, but our faith is not central. Oftentimes it is translated “faith in Christ,” which still puts Christ as the object of faith, but also emphasizes our faith. And there’s no doubt that there is an emphasis on human faith, such as in the case of Abraham in Romans 4. And that our faith is contrasted to our works, and specifically to the works of the Law. So that grace is grace only if it is by faith and not by works, I think not so much with regard to human effort, but more in terms of adherence to the Law of Moses. It’s a bit complicated, but even in that case in Romans 4, I think Paul is simply trying to show that it is faith in God’s word, and specifically in the gospel which justifies or brings salvation, and to think that works of the Law enter in, is to bring in a category which is actually as foreign to the First/Old Testament, as it is to the Final/New Testament. Abraham was justified by faith apart from the works of the Law, and before he was circumcised. The boasting Paul says is to be rejected is not really about one’s own effort, and not even a smidgen about some supposed moral perfection, even if Paul uses the latter to point out that those who emphasize Law/Torah keeping must not break any of it to remain in the clear with God. The boasting by the Jew would be in the Torah itself, and the fact that they possessed and sought to live by that Torah/Law.
But to the main point of this post. The faithfulness of Christ in his coming, life, and especially in his death, followed by God’s vindication in his resurrection from the dead, then his ascension to the supreme place of authority at God’s right hand, with the promise of his return when the final judgment and salvation come and in that, the new creation, is what our focus should be on. Not our own faith, but on the faithfulness of Christ. It is far better to have a small faith in a great object, instead of a large faith in a small object. The focus must not be on our own faith, but on the faithfulness of God in Christ, yes, on the faithfulness of Christ. That is the focus in which our faith can be established and grow.