There are two Hebrew words for “repent” – nacham means “be sorry” or “comfort,” while shuwb means “turn” or “return.” The Greek equivalent (metanoeo) is a combination of meta (“after,” “with”) and noeo (“understand,” “think”), commonly understood to mean “change one’s mind.” In Jewish theology, repentance was turning one's heart away from immorality and submitting to God’s sovereignty. It was paramount to Jewish religion, and was the basis for making animal sacrifices to cover sin.
Nearly every prophet in Israel's history called people to repentance and reconciliation with God. The entire nation repented from worshiping a golden calf during its journey through the desert after Moses’ rebuke. King David famously repented after sleeping with Uriah’s wife, Bathsheba, as recorded in the remorseful Psalm 51. The Bible even records that the great Babylonian king Nebuchadnezzar repented and worshipped God after a period of insanity and isolation.
If my people, who are called by my name, will humble themselves, pray, seek my face, and turn from their evil paths, then I’ll hear from heaven, forgive their sin, and heal their land.
– 2 Chronicles 7:14