An altar of stone in those rocky parts might be as easy for them to make as one of earth. Hewn stone would require both time, and cost, and art. The reasons of this precept are in part the same with the former, Exodus 20:24. If thou lift up thy tool upon it, thou hast polluted it, by thy disobedience to my express command now given; and howsoever they think to gratify me by this curiosity, I shall not look upon it as a sacred thing, by which the sacrifices offered on it shall be sanctified, but as a profane thing which will defile them. So little doth God value or approve the inventions of men in his worship, how colourable soever they be.
Related Commentaries of Exodus 20:25
Exodus 20:25
25 And if thou wilt make me an altar of stone, thou shalt not buildb it of hewn stone: for if thou lift up thy tool upon it, thou hast polluted it.