Deuteronomy 25:17-19

Remember what the Amalekites did to you when you came out of Egypt. When you were tired and worn out, they met you on the road and attacked all those lagging behind. They were not afraid of God. When the LORD your God gives you rest from all the enemies around you in the land he is giving you as your own, you shall destroy any memory of the Amalekites on the earth. Do not forget!