CCC 1105 The Epiclesis (“invocation upon”) is the intercession in which the priest begs the Father to send the Holy Spirit, the Sanctifier, so that the offerings may become the body and blood of Christ and that the faithful by receiving them, may themselves become a living offering to God.1

CCC 1454 The reception of this sacrament ought to be prepared for by an examination of conscience made in the light of the Word of God. The passages best suited to this can be found in the Ten Commandments, the moral catechesis of the Gospels and the apostolic letters, such as the Sermon on the Mount and the apostolic teachings.2

CCC 2031 The moral life is spiritual worship. We “present [our] bodies as a living sacrifice, holy and acceptable to God,”3 within the Body of Christ that we form and in communion with the offering of his Eucharist. In the liturgy and the celebration of the sacraments, prayer and teaching are conjoined with the grace of Christ to enlighten and nourish Christian activity. As does the whole of the Christian life, the moral life finds its source and summit in the Eucharistic sacrifice.

CCC 2520 Baptism confers on its recipient the grace of purification from all sins. But the baptized must continue to struggle against concupiscence of the flesh and disordered desires. With God’s grace he will prevail
– by the virtue and gift of chastity, for chastity lets us love with upright and undivided heart;
– by purity of intention which consists in seeking the true end of man: with simplicity of vision, the baptized person seeks to find and to fulfill God’s will in everything;4
– by purity of vision, external and internal; by discipline of feelings and imagination; by refusing all complicity in impure thoughts that incline us to turn aside from the path of God’s commandments: “Appearance arouses yearning in fools”;5
– by prayer:
I thought that continence arose from one’s own powers, which I did not recognize in myself. I was foolish enough not to know. .. that no one can be continent unless you grant it. For you would surely have granted it if my inner groaning had reached your ears and I with firm faith had cast my cares on you.6

CCC 2826 By prayer we can discern “what is the will of God” and obtain the endurance to do it.7 Jesus teaches us that one enters the kingdom of heaven not by speaking words, but by doing “the will of my Father in heaven.”8

1 Cf. Rom 12:1.
2 Cf. Mt 5-7; Rom 12-15; 1 Cor 12-13; Gal 5; Eph 4-6; etc.
3 Rom 12:1.
4 Cf. Rom 12:2; Col 1:10.
5 Wis 15:5.
6 St. Augustine, Conf. 6, 11, 20: PL 32, 729-730.
7 Rom 12:2; Cf. Eph 5:17; Cf. Heb 10:36.
8 Mt 7:21.