Information about this penitential prayer
The Act of Contrition is a prayer from the Catholic tradition expressing sorrow for one's sins and spiritual shortcomings. It's a popular prayer for use in personal devotion and is sometimes used in the sacrament of confession. In Latin it is called the Actus Contritionis. Many people say it nightly as a way to end the day with a clean conscience. There are many different versions of this prayer.
Act of Contrition
O my God,
I am heartily sorry for having offended You.
I detest all my sins because of your just punishment,
But most of all because they offend you, my God, who are all-good and deserving of all my love.
I firmly resolve, with the help of Your grace, to sin no more and to avoid the near occasions of sin.