Deuteronomy 27:5
Moreover, you are to build there an altar to the LORD your God, an altar of stones. You must not use any iron tool on them.
Berean Standard Bible
And there shalt thou build an altar unto the LORD thy God, an altar of stones: thou shalt not lift up any iron tool upon them.
There you shall build an altar to the LORD your God, an altar of stones. You shall not use any iron tool on them.