Exodus 20:25

If you make me an altar of stone, you must not build it ¹  of stones shaped with tools, ²  for if you use your tool on it you have defiled it. ³ 

De 27:5,6; Jos 8:31

¹ tn Heb “them” referring to the stones.

² tn Heb “of hewn stones.” Gesenius classifies this as an adverbial accusative – “you shall not build them (the stones of the altar) as hewn stones.” The remoter accusative is in apposition to the nearer (GKC 372 §117.kk).

³ tn The verb is a preterite with vav (ו) consecutive. It forms the apodosis in a conditional clause: “if you lift up your tool on it…you have defiled it.”