Charles Ellicott Commentary Deuteronomy 27:5

"And there shalt thou build an altar unto Jehovah thy God, an altar of stones: thou shalt lift up no iron [tool] upon them." — Deuteronomy 27:5 (ASV)

An altar of stones. —Rashi propounds the theory that these stones were taken from Jordan. But there is nothing to support this theory in the words of the text.