Exodus 20:22-26 - Instructions For Building Altars
22 Then said Yahweh unto Moses, Thus, shalt thou say, unto the sons of Israel, - Ye yourselves, have seen that out of the heavens, have I spoken with you. 23 Ye shall not make aught beside me, - neither gods of silver, nor gods of gold, shall ye make to yourselves.
24 An altar of earth, shalt thou make to me, then shalt thou offer thereupon thine ascending-sacrifices and thy peace-offerings, thy sheep, and thine oxen. In every place where I may mention my name, will I come in unto thee and will bless thee. 25 But if, an altar of stones, thou wilt make to me, thou shalt not build them hewn, - for as soon as thou hast lifted, thy sharp tool, thereupon, thou hast profaned it; 26 neither shalt thou go up, by steps unto mine altar, - lest by any means thy shame be discovered thereupon.