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 Commandants, the moral catechesis of the Gospels and the apostolic Letters, such as the Sermon on the Mount and the apostolic teachings. (CCC1454)
It is recommended that individuals pray for help to make a good confession and do an Examination of Conscience prior to reception of this sacrament.
O Holy Spirit. Source of all light, Spirit of wisdom, of understanding, and of knowledge, come to my assistance and enable me to make a good confession. Enlighten me, and help me now to know my sins as one day I shall be force to recognize them before Thy judgment seat. Bring to my mind the evil which I have done and the good which I have neglected. Permit me not to be blinded by self-love. Grant me, moreover, heartfelt sorrow for my transgressions, and the grace of a sincere confession, so that I may be forgiven and admitted into Thy friendship.