Backslide
Backsliding refers to a falling away or apostasy from a previously held religious commitment — a drawing back from the living God into sin, unbelief, or idolatry. The term appears prominently in Jeremiah and Hosea as a description of Israel's recurring pattern of covenant unfaithfulness: The backsliding Israel hath justified herself more than treacherous Judah (Jeremiah 3:11). Proverbs 14:14 notes that the backslider in heart shall be filled with his own ways — the consequences of departure from God are self-generated.
In the New Testament, the concept appears without the specific Hebrew term in warnings about apostasy and falling away. Paul warns of a coming departure from the faith (2 Thessalonians 2:3; 1 Timothy 4:1), and the writer of Hebrews devotes extensive argument to the danger and irrecoverability of deliberate apostasy (Hebrews 6:4–6; 10:26–31, 38–39). The consistent biblical pattern treats backsliding not as inevitable but as a mortal danger with genuine remedies: confession, repentance, and return to God, as Jeremiah 3:22 and Hosea 14:1–4 make plain.