Cross reference
Exodus 20:25
25 `And if an altar of stones thou dost make to Me, thou dost not build them of hewn work; when thy tool thou hast waved over it, then thou dost pollute it;
Deuteronomy 27:5-6
5 and built there an altar to Jehovah thy God, an altar of stones, thou dost not wave over them iron.
6 Of complete stones thou buildest the altar of Jehovah thy God, and hast caused to ascend on it burnt-offerings to Jehovah thy God,
Joshua 8:31
31 as Moses, servant of Jehovah, commanded the sons of Israel, as it is written in the book of the law of Moses -- an altar of whole stones, over which he hath not waved iron -- and they cause to go up upon it burnt-offerings to Jehovah, and sacrifice peace-offerings;