Why Strike the Breast When Confessing Sins?

Q. Why do we strike our breasts when we confess our sins during Mass?

A. Striking the breast is an ancient sign of penitence or sorrow. In the Gospel, for example, the penitent tax collector “beat his breast” as he prayed for God’s mercy. The sorrowful multitudes who had watched Jesus die on the Cross “returned home beating their breasts” (Luke 18:13; 23:48).

Ancient Christians testify to the practice as well. St. Augustine observed that by this gesture “you wish to bring to light what is concealed in the breast, and by this to cleanse your hidden sins” (Sermo de verbis Domini, 13). St. Jerome insisted: “We strike our breast because the breast is the seat of evil thoughts; we wish to dispel these thoughts; we wish to purify our hearts” (In Ezechiel, c. xviii).