When God touches man's heart through the illumination of the Holy Spirit, man himself is not inactive while receiving that inspiration, since he could reject it; and yet, without God's grace, he cannot by his own free will move himself toward justice in God's sight. 42
Catechism number 1995
The Holy Spirit is the master of the interior life. By giving birth to the "inner man,"44 justification entails the sanctification of his whole being: