The Act of Contrition is part of the Sacrament of Penance and is prayed by the penitent after the priest assigns a penance and before he gives the penitent absolution. It is also customarily said especially before one goes to bed at night. It is generally supposed that individuals might have recourse to an Act of Contrition when they find themselves in extremis.
The prayer expresses in words a deeply personal “act” that engages a person’s affections and will. Catholic teaching holds that “imperfect” contrition, is also a gift of God. Born of fear of eternal damnation or other penalties, it is nonetheless sufficient to inspire a valid Act of Contrition. There are different versions of the Act of Contrition, but all generally include an expression of sorrow, an acknowledgment of wrongdoing and a promise to amend one’s life and avoid sin.