וּבָנִ֤יתָ שָּׁם֙ מִזְבֵּ֔חַ לַיהוָ֖ה אֱלֹהֶ֑יךָ מִזְבַּ֣ח אֲבָנִ֔ים לֹא־תָנִ֥יף עֲלֵיהֶ֖ם בַּרְזֶֽל׃
And there shalt thou build an altar unto the LORD thy God, an altar of stones; thou shalt lift up no iron tool upon them.
Targum Jonathan on Deuteronomy
and you shall build there an altar before the Lord your God, an altar of stone, not lifting up iron upon it.