Exodus 20:25
If you make an altar of stone for me, you must not build it of cut stones, because if you strike it with your chisel, you will profane it.
Deuteronomy 27:5-6
Then build an altar there to the LORD your God, an altar of stones that hasn't been worked with iron tools.
Joshua 8:31
just the way Moses the servant of the LORD had commanded the Israelis in the Book of the Law of Moses: ""an altar of uncut stones that hasn't been worked with iron tools"" and they offered burnt offerings to the LORD on it, along with 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
Then build an altar there to the LORD your God, an altar of stones that hasn't been worked with iron tools.
Joshua 8:31
just the way Moses the servant of the LORD had commanded the Israelis in the Book of the Law of Moses: ""an altar of uncut stones that hasn't been worked with iron tools"" and they offered burnt offerings to the LORD on it, along with peace offerings.
General references
Leviticus 16:33
and make atonement for the sacred sanctuary, the Tent of Meeting, and the altar where atonement is carried out. He is also to make atonement for the priests and the people of the entire assembly.