Peter had no reason to brag about his knowledge of Christ to the other apostles, since it was he who got the right answer first. He didn’t find it out for himself.
You are blessed, Simon son of Jonah, because flesh and blood did not reveal this to you, but my Father in heaven!
Matthew 16.17 NET
Even hearing the gospel of Christ is a gift of grace, since it comes by God’s revelation.
In that vein, Quick Bible Truths says today: “Certainty in the gospel does not generate pride, but humility, for it is the product of God’s revelation, rather than a believer’s research.” (The Bible can even call repentance something that God grants, Acts 11.18).
None of this diminishes our responsibility. But if God did not speak, we could not hear. If there were no revelation of the mind of God, we could not confess the truth of Christ. If there were no divine holiness for us to see and no command in place, repentance would be impossible.
So while we retain that responsibility, there is no credit accrued for our response.
It is truly the gospel of the grace of God.