5 Now we have only to open the sacred books of the Old and New Testament to be assured of one thing: it was never God's will to reveal Himself in any solemn encounter with mortal men—to speak in human terms—without first calling them to prayer and penance. Indeed, Moses refused to give the Hebrews the tables of the Law until they had expiated their crime of idolatry and ingratitude.(5)
Source: Paenitentiam Agere (Vatican.va)