Deuteronomy 25:17-19

17“1Remember what Amalek did to you on the way when you came out of Egypt,

18how he confronted you on the way and attacked among you all the stragglers at your rear when you were tired and weary; and he 2did not 3fear God.

19So it shall come about, when the Lord your God has given you 4rest from all your surrounding enemies in the land which the Lord your God is giving you as an inheritance to 5possess, that you shall wipe out the mention of the name Amalek from under heaven; you must not forget.