Catholic Catechism:
1993 Justification establishes cooperation between God’s grace and man’s freedom. On man’s part it is expressed by the assent of faith to the Word of God, which invites him to conversion, and in the cooperation of charity with the prompting of the Holy Spirit who precedes and preserves his assent:
*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 *
2002 God’s free initiative demands man’s free response, for God has created man in his image by conferring on him, along with freedom, the power to know him and love him. The soul only enters freely into the communion of love. God immediately touches and directly moves the heart of man. He has placed in man a longing for truth and goodness that only he can satisfy. The promises of “eternal life” respond, beyond all hope, to this desire:
2005 Since it belongs to the supernatural order, grace escapes our experience and cannot be known except by faith. We cannot therefore rely on our feelings or our works to conclude that we are justified and saved.56 However, according to the Lord’s words "Thus you will know them by their fruits"57 - reflection on God’s blessings in our life and in the lives of the saints offers us a guarantee that grace is at work in us and spurs us on to an ever greater faith and an attitude of trustful poverty.
*A pleasing illustration of this attitude is found in the reply of St. Joan of Arc to a question posed as a trap by her ecclesiastical judges: "Asked if she knew that she was in God’s grace, she replied: ‘If I am not, may it please God to put me in it; if I am, may it please God to keep me there.’"58 *