Exodus 20:25
If you make me an altar of stone, you shall not build it of hewn stones, for if you wield your tool on it you profane it.
Deuteronomy 27:5-6
And there you shall build an altar to the LORD your God, an altar of stones. You shall wield no iron tool on them;
Joshua 8:31
just as Moses the servant of the LORD had commanded the people of Israel, as it is written in the Book of the Law of Moses, "an altar of uncut stones, upon which no man has wielded an iron tool." And they offered on it burnt offerings to the LORD and sacrificed peace offerings.
Treasury of Scripture Knowledge
Summary
And if thou wilt make me an altar of stone, thou shalt not build it of hewn stone: for if thou lift up thy tool upon it, thou hast polluted it.
General references
Bible References
And
Deuteronomy 27:5
And there you shall build an altar to the LORD your God, an altar of stones. You shall wield no iron tool on them;
Joshua 8:31
just as Moses the servant of the LORD had commanded the people of Israel, as it is written in the Book of the Law of Moses, "an altar of uncut stones, upon which no man has wielded an iron tool." And they offered on it burnt offerings to the LORD and sacrificed peace offerings.
General references
Leviticus 16:33
He shall make atonement for the holy sanctuary, and he shall make atonement for the tent of meeting and for the altar, and he shall make atonement for the priests and for all the people of the assembly.