again, the law of faith excludes boasting. If you could believe all on your own you could boast about it. God says you can’t.
The grace of God which brings salvation has appeared to ALL men. How a person responds to that determines the level of revelation and faith he is then given. There can never be any boasting at all because we are given a gift - the giver has done it all in order to be able to give it - and we accept that gift through faith. We cannot boast because faith is not a “work” that makes a payment for sin. It is only through the blood of Christ that we are offered eternal life. There is nothing we CAN do to earn or merit it and that is why “it” (being saved by grace) is a gift.