Exodus 34:27

Then Yahweh said to Moses, “Write this in a book as a memorial and recite it in Joshua’s hearing, that I will utterly blot out the memory of Amalek from under heaven.”

And Moses wrote down all the words of Yahweh. Then he arose early in the morning and built an altar at the foot of the mountain with twelve pillars for the twelve tribes of Israel.

Then God said, “Behold, I am going to cut a covenant. Before all your people I will do wondrous deeds which have not been created in all the earth nor among any of the nations; and all the people among whom you live will see the working of Yahweh, for it is a fearful thing that I am going to do with you.