Deuteronomy 27:5-7

Amplified Bible

⁵ There you shall build an altar to the Lord your God, an altar of stones; you shall not use an iron tool on them. ⁶ You shall build the altar of the Lord your God with whole [uncut] stones, and offer burnt offerings on it to the Lord your God; ⁷ and you shall sacrifice peace offerings and shall eat there, and shall rejoice before the Lord your God.