Deuteronomy 27:5-6

27:5 Then you must build an altar there to the Lord your God, an altar of stones – do not use an iron tool on them. 27:6 You must build the altar of the Lord your God with whole stones and offer burnt offerings on it to the Lord your God.

Joshua 8:31

8:31 just as Moses the Lord’s servant had commanded the Israelites. As described in the law scroll of Moses, it was made with uncut stones untouched by an iron tool. ¹  They offered burnt sacrifices on it and sacrificed tokens of peace. ² 

[8:31]  ¹ tn Heb “as it is written in the scroll of the law of Moses, an altar of whole stones on which no one had wielded iron.” The expression “whole stones” refers to stones in their natural condition, i.e., not carved or shaped artificially with tools (“wielded iron”).

[8:31]  ² tn Or “peace offerings.”