Exodus 20:24

An altar of earth thou shalt make unto me. — The earliest altars were, naturally, either of earth, or of unhewn stones, gathered into a heap, since these could be constructed with little labour, and without tools. But, as civilisation advanced, more elaborate structures took the place of the primitive ones. It became usual to erect altars of hewn stone, adorned with carvings more or less rich, among which might often be introduced human and animal forms. We must understand the command here given, and that of Exodus 20:25, as intended to forbid structures of this latter kind, which, if allowed, might have led on to idolatry.

Thy burnt offerings and thy peace offerings. — Sacrifice began soon after Paradise was quitted (Genesis 4:3), and shortly became a universal practice. Noah offered sacrifice on leaving the ark (Genesis 8:20); and in the family of Abraham the rite was an established one (Genesis 12:7; Genesis 15:9; Genesis 22:7; Genesis 26:25; Genesis 31:54, &c.). Egyptians, Assyrians, Babylonians, Persians, Phœnicians, Greeks, Romans, Scythians, Celts, Germans, all equally regarded sacrifice as a main element of their religion; and if the Hebrews had not offered actual sacrifices during their oppression in Egypt, they had, at any rate, maintained the wish to offer them, and it was (primarily) for the purpose of sacrificing that they had quitted Egypt. The legislation assumes that they are acquainted with the difference between “burnt offerings and “peace offerings,” and desirous of offering both kinds.