The platform used to offer animal sacrifice or burnt offerings to a god. Other offering rituals include burning incense (Exodus 30:1–10). The Hebrew word for altar and the verb "to slaughter" both come from the same root word. The meaning of both words refers to ritual sacrifice of animals to God as a covering for sin. Many communities in the ancient Middle East practiced this type of sacrifice. Israel’s neighbors the Canaanites had their own altars and rituals. The altar was always a raised-up place.
The Bible refers to several altars built by people in the Old Testament:
Noah offered burnt offerings (Genesis 8:20).
Abraham built an altar at Shechem, another at Bethel, and one on Mount Moriah (Genesis 12:7; 12:8; 22:9).
Isaac built an altar at Beersheba (Genesis 26:25),
Jacob built an altar at Shechem and Bethel ((Genesis 33:20; 35:7).
Moses built one at Rephidim and another at Horeb ((Exodus 17:15; 24:4).
In each case, the individual erected the altar to commemorate help received from God.
The description of the tabernacle in Exodus 25—27 included two altars. The larger altar, made of acacia wood overlaid with bronze, measured 5 by 5 by 3 cubits (2.3 by 2.3 by 1.4 meters or 7.5 by 7.5 by 4.5 feet). This was the altar used for burnt offerings (Exodus 27:1–8; 38:1–7). The smaller golden altar for burning incense measured about 45 centimeters (18 inches) square and 90 centimeters (3 feet) high (Exodus 30:1–10; 40:5).
In Exodus 20:24–26, God instructed Israel to make an altar from earth or uncut stones. God commanded Israel to offer burnt offerings and peace offerings in "every place where God caused his name to dwell." This is why individuals build altars throughout the Old Testament:
Joshua built an altar on Mount Ebal (Joshua 8:30–31).
The Reubenites, Gadites, and the half-tribe of Manasseh built an altar in Transjordan (Joshua 22:10–16).
Gideon built an altar in Ophrah (Judges 6:24).
The family of David built an altar in Bethlehem (1 Samuel 20:6, 29).
David built an altar at the threshing floor of Araunah (2 Samuel 24:25). A threshing floor is a flat area where grain is separated from stalks.
Elijah built an altar on Mount Carmel (1 Kings 18:30).
People built all these altars, except Elijah's on Mount Carmel, before Solomon's temple existed.
Like the tabernacle, Solomon’s temple included 2 altars. One was 20 cubits square (about 7.6 meters or 25 feet) and 10 cubits high (about 3.8 meters or 12.5 feet). Made of bronze and used for burnt offerings, this altar was the center of temple worship. King Ahaz removed the bronze altar from its place at the command of the Assyrian ruler Tiglath-pileser (2 Kings 16:14). This altar was later restored to its proper place by Hezekiah (2 Chronicles 29:18). The second altar for incense, made of cedar and overlaid with gold, stood in front of the veil (1 Kings 6:20–22).
The destruction of Solomon's temple and the exile of the Jewish people made the prophet Ezekiel dream of restoring the temple. In his vision, the sacrificial altar rose in three levels to 10 cubits high (5.3 meters or 17.5 feet). The tall altar rested on a base about 20 cubits (35 feet or 10.6 meters) square. This outsized altar emphasized the need for atonement in Israel (Ezekiel 43:13–17). No reference to an incense altar appeared in the vision.
Zerubbabel built an altar of burnt offerings (Ezra 3:2). Antiochus Epiphanes desecrated this altar (made it unclean), probably with an image of Zeus (1 Maccabees 1:54). There was also an altar of incense. Antiochus Epiphanes removed the golden altar (1 Maccabees 1:21) in 169 BC. Both were later restored by Judas Maccabeus (1 Maccabees 4:44–49).
Christian worship does not require a sacrificial altar. The death of Jesus Christ serves as the final sacrifice for sin. The Bible often refers to the altar of burnt offering and the altar of incense (Matthew 5:23–24; 23:18–20, 35; Luke 11:51; 1 Corinthians 9:13; 10:18; Hebrews 7:13; Revelation 11:1) . Some references apply to the earthly temple (Luke 1:11). Other references apply to the heavenly temple (Revelation 6:9; 8:5; 9:13).