Before approaching the tribunal of Penance, the penitent must make an examination of conscience, with a carefully effort to remember all the sins committed since his last confession. It is particularly necessary to confess the mortal sins committed after Baptism that have not yet been directly forgiven by the power of the keys.
In order to make a good examination of conscience, the penitent will invoke God’s help:
O Holy Ghost, eternal source of light, dispel the shadows that hide from me the ugliness and malice of sin. Give me so great a horror for sin, O my God, that I may hate it, if possible, as much as Thou dost hate it, and that I may fear nothing so much as to commit it again.
He will carefully recall to mind the sins he has committed by thought, word, action or omission against the commandments of God and of the Church, and against his duty of state. He will mention the circumstances that could make a venial sin mortal, the number of times the sins were committed, the harm caused, etc.
If he has any trouble entering into his inner self, the penitent will not hesitate to seek help, either by using a missal or prayer book or by asking the priest to help him, always asking God and especially the Holy Ghost to help him see his faults and negligence more clearly.