Faith is a gift...but it is a measure of faith. It's not the whole enchilada. With the Holy Spirit in us...guiding us...Jesus does continue to perfect our faith.
Romans 12:3
3 For I say, through the grace given unto me, to every man that is among you, not to think of himself more highly than he ought to think; but to think soberly, according as God hath dealt to every man the measure of faith.
We should not take credit for our faith because then we get boastful. We should give Him all the glory for what He is doing in our lives.