Altar in Fausset's Bible Dictionary

The first of which we have mention was built by Noah after leaving the ark (Genesis 8:20). The English (from the Latin) means an elevation or high place: not the site, but the erections on them which could be built or removed (1 Kings 12:7; 2 Kings 23:15). So the Greek bomos, and Hebrew bamath. But the proper Hebrew name mizbeach is "the sacrificing place;" Septuagint thusiasterion. Spots hallowed by divine revelations or appearances were originally the sites of altars (Genesis 12:7; Genesis 13:18; Genesis 26:25; Genesis 35:1). Mostly for sacrificing; sometimes only as a memorial, as that named by Moses Jehovah Nissi, the pledge that Jehovah would war against Amalek to all generations (Exodus 17:15-16), and that built by Reuben, Gad, and half Manasseh, "not for burnt offering, nor sacrifice, but as a witness" (Joshua 22:26-27). Altars were to be made only of earth or else unhewn stone, on which no iron tool was used, and without steps up to them (Exodus 20:24-26). Steps toward the E. on the contrary are introduced in the temple yet future (Ezekiel 43:17), marking its distinctness from any past temple. No pomp or ornament was allowed; all was to be plain and simple; for it was the meeting place between God and the sinner, and therefore a place of shedding of blood without which there is no remission (Leviticus 17:11; Hebrews 9:22), a place of fellowship with God for us only through death. The mother dust of earth, or its stones in their native state as from the hand of God, were the suitable material. The art of sinful beings would mar, rather than aid, the consecration of the common meeting ground. The earth made for man's nourishment, but now the witness of his sin and drinker in of his forfeited life, was the most suitable (see Fairbairn, Typology). The altar was at "the door of the tabernacle of the tent of the congregation" (Exodus 40:29)...