Deuteronomy 27:5
There you are to make an altar to the Lord your God, of stones on which no iron instrument has been used.
Exodus 20:25
And if you make me an altar of stone do not make it of cut stones: for the touch of an instrument will make it unclean.
Exodus 24:4
Then Moses put down in writing all the words of the Lord, and he got up early in the morning and made an altar at the foot of the mountain, with twelve pillars for the twelve tribes of Israel.
Joshua 8:30-31
Then Joshua put up an altar to the Lord, the God of Israel, in Mount Ebal,
1 Kings 18:31-32
And Elijah took twelve stones, the number of the tribes of the sons of Jacob, to whom the Lord had said, Israel will be your name: