5 "The obedience of faith" (Rom. 16:26; see 1:5; 2 Cor 10:5-6) "is to be given to God who reveals, an obedience by which man commits his whole self freely to God, offering the full submission of intellect and will to God who reveals," and freely assenting to the truth revealed by Him. To make this act of faith, the grace of God and the interior help of the Holy Spirit must precede and assist, moving the heart and turning it to God, opening the eyes of the mind and giving "joy and ease to everyone in assenting to the truth and believing it." To bring about an ever deeper understanding of revelation the same Holy Spirit constantly brings faith to completion by His gifts.
Source: Dei Verbum (Vatican.va)