Deuteronomy 25:19

Therefore it shall be, when the LORD thy God hath given thee rest from all thine enemies round about, in the land which the LORD thy God giveth thee [for] an inheritance to possess it, [that] thou shalt blot out the remembrance of Amalek from under heaven; thou shalt not forget [it].

Ver. 19. Thou shalt not forget it.] Neither did they. Saul should have utterly destroyed them, 1Sa 15:18-19 but wherein he failed, God stirred up the Simeonites in Hezekiah's days to smite the rest of the Amalekites that were escaped. 1Ch 4:42-43 It is ill angering the Ancient of days. His wrath lasts longer than hot coals of juniper, Psa 120:4 his judgments are severe and durable: as we use to say of winter frosts, they never rot in the sky, but shall fall, if late, yet surely, yet seasonably. God's forbearance is no quittance.