She did/performed (an act of) 'penance' for her sins.
He did charitable work as a 'penance'.
(..) an angel to do his will. For surely there is no better soldier for God than my Silas. I firmly resolve, with the help of thy grace, to confess my sins... ...to do penance and to amend my life. Amen. I chastise my body. The Holy Grail. A magic cup. (..)2006 The Da Vinci Code