The Act of Contrition is a prayer said during Confession. The prayer expresses the penitent’s sorrow for their sins and for offending God. The prayer concludes by the penitent making an affirmation to perform an act of penance and amend his life. There are several variations of the Act of Contrition. Below is a good version of this prayer:
O my God, I am heartily sorry for having offended Thee, and I detest all my sins, because I dread the loss of heaven, and the pains of hell; but most of all because they offend Thee, my God, Who are all good and deserving of all my love. I firmly resolve, with the help of Thy grace, to confess my sins, to do penance, and to amend my life.
Amen.