Deuteronomy 25:17-19

17Remember what the Amalekites did to you along the way when you came out of Egypt. 18When you were weary and worn out, they met you on your journey and attacked all who were lagging behind; they had no fear of God. 19When the LORD your God gives you rest from all the enemies around you in the land he is giving you to possess as an inheritance, you shall blot out the name of Amalek from under heaven. Do not forget!