Deuteronomy 27:5 in the World English Bible
There you shall build an altar to the LORD your God, an altar of stones. You shall not use any iron tool on them.
Context
4 Therefore it shall be when ye be gone over Jordan, that ye shall set up these stones, which I command you this day, in mount Ebal, and thou shalt plaister them with plaister.
5 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.
6 Thou shalt build the altar of the LORD thy God of whole stones: and thou shalt offer burnt offerings thereon unto the LORD thy God: