1. be sorry for his sins
2. confess all certain mortal sins since the last good confession
3. do the penance imposed by the priest.

Contrition is defined by theologians and the Council of Trent as “a deep sorrow and detestation for sin committed, with a resolution of sinning no more” (DS 1676). Interior and sincere contrition of this kind has always been necessary to obtain the forgiveness of sins and it is necessary to receive the Sacrament properly.

We all learned in catechism lessons that there are two kinds of contrition—perfect and imperfect. The difference between them is found in the motive. Perfect contrition is motivated by the goodness and love of God above all things. Such contrition forgives mortal sins, even outside the Sacrament of Penance, but it must include (at least implicitly) the intention of going to confession at the first opportunity. All our parishioners should be urged to try to make an act of perfect contrition, if through human weakness they should fall into mortal sin, and resolve to go to confession as soon as they can.

Imperfect contrition is also called “attrition.” It is defined as sorrow for sin for a motive less than the love of God, such as the ugliness of sin or the fear of hell. Attrition is a gift of God and a result of his actual grace, but in order to forgive mortal sin it must be joined to receiving absolution from the priest in confession. It is incumbent on the priest-confessor to make sure that each penitent makes his confession with a sorrow for his sins that is at least attrition. For without that the confession is invalid. For confession is not like a vending machine into which one puts money, presses a button, and out pops a candy bar; this procedure requires coins—the subjective disposition of the buyer is irrelevant. In order for mortal sins to be forgiven in confession the penitent must be truly sorry for all of his mortal sins.

Many of our good Catholics who go to confession regularly do not have mortal sins to confess; they confess venial sins or imperfections. Venial sins are not necessary matter for confession, but they are sufficient matter. Venial sins can be forgiven outside of confession by prayers, penances, attending Mass, almsgiving, and so forth. These good people should be instructed that it is not enough just to mention their venial sins; in order to receive absolution validly they must also be truly sorry for at least one of their venial sins. I think it is a good practice in such cases to ask the penitent if he is sorry for all the sins of his past life. The reason for that is to make sure that there is sufficient matter for absolution and it also helps the penitent elicit a true act of contrition.

An important aspect of true contrition is purpose of amendment. This means that the penitent has a sincere will to amend his life, that he will take the means necessary to avoid sin and the proximate occasions of sin (such as watching certain TV shows), and it must include all mortal sins in general. If this is lacking the priest cannot absolute the penitent.

Many Catholics do not know how to make a good confession. It is up to us priests to instruct them on how to receive this great Sacrament fruitfully. There is much grace, consolation and peace of soul to be gained by approaching the tribunal of Divine Mercy in the way prescribed by Christ Our Lord and his Church. No Catholic should be deprived of these graces because of ignorance.