Act of Contrition

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 art 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.

(in slightly dated diction, via TRADITIONAL CATHOLIC PRAYERS)