CCC
Faith is a human act
154 Believing is possible only by grace and the interior helps of the Holy Spirit. But it is no less true that believing is an authentically human act. Trusting in God and cleaving to the truths he has revealed is contrary neither to human freedom nor to human reason. Even in human relations it is not contrary to our dignity to believe what other persons tell us about themselves and their intentions, or to trust their promises (for example, when a man and a woman marry) to share a communion of life with one another. If this is so, still less is it contrary to our dignity to “yield by faith the full submission of… intellect and will to God who reveals”,26 and to share in an interior communion with him.
155 In faith, the human intellect and will co-operate with divine grace: "Believing is an act of the intellect assenting to the divine truth by command of the will moved by God through grace."27
654 The Paschal mystery has two aspects: by his death, Christ liberates us from sin; by his Resurrection, he opens for us the way to a new life. This new life is above all justification that reinstates us in God’s grace, “so that as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life.” Justification consists in both victory over the death caused by sin and a new participation in grace.526 It brings about filial adoption so that men become Christ’s brethren, as Jesus himself called his disciples after his Resurrection: "Go and tell my brethren."527 We are brethren not by nature, but by the gift of grace, because that adoptive filiation gains us a real share in the life of the only Son, which was fully revealed in his Resurrection.
2010 Since the initiative belongs to God in the order of grace, no one can merit the initial grace of forgiveness and justification, at the beginning of conversion. Moved by the Holy Spirit and by charity, we can then merit for ourselves and for others the graces needed for our sanctification, for the increase of grace and charity, and for the attainment of eternal life. Even temporal goods like health and friendship can be merited in accordance with God’s wisdom. These graces and goods are the object of Christian prayer. Prayer attends to the grace we need for meritorious actions.
2011 The charity of Christ is the source in us of all our merits before God. Grace, by uniting us to Christ in active love, ensures the supernatural quality of our acts and consequently their merit before God and before men. the saints have always had a lively awareness that their merits were pure grace.
After earth’s exile, I hope to go and enjoy you in the fatherland, but I do not want to lay up merits for heaven. I want to work for your love alone… In the evening of this life, I shall appear before you with empty hands, for I do not ask you, Lord, to count my works. All our justice is blemished in your eyes. I wish, then, to be clothed in your own justice and to receive from your love the eternal possession of yourself.63