After the Sign of the Cross and the Greeting, the next part of the Introductory Rites of the Mass is the Penitential Act. It is a fundamental fact of the human condition that we are all sinners. The Apostle Paul said, “Christ Jesus came into the world to save sinners. Of these I am the foremost” (1 Tm 1:15). When the Lord Jesus first got into Peter’s boat, and Peter experienced the miraculous catch of fish, he said to the Lord, “Depart from me, Lord, for I am a sinful man” (Lk 5:8). Every genuine encounter with the living God makes us keenly aware of our sinful condition, and we can have no encounter with God greater and more intimate than the Mass, where we “are nourished by the Body and Blood” of His Son (Eucharistic Prayer III).
In his recent catechesis on the Mass, Pope Francis explained the deep significance of the Penitential Act at the beginning of the Mass: “In its sobriety, it favours the attitude with which we are prepared to worthily celebrate the holy mysteries, that is, by acknowledging our sins before God and our brothers and sisters, acknowledging that we are sinners. In fact the priest’s invitation is addressed to the whole community in prayer, because we are all sinners. What can the Lord give to one whose heart is already filled with self-importance, with one’s own success? Nothing, because a presumptuous person is incapable of receiving forgiveness, as he is satisfied by his presumed righteousness. Let us consider the parable of the Pharisee and the tax collector, where only the latter — the tax collector — returns home justified, that is, forgiven (cf. Lk 18:9-14). One who is aware of his own wretchedness and lowers his gaze with humility feels God’s merciful gaze set upon him. We know through experience that only one who is able to acknowledge his mistakes and apologize receives the understanding and forgiveness of others” (January 3, 2018).