The scapegoat was a goat that was designated (Hebrew לַעֲזָאזֵֽל ) la-aza'zeyl; either "for absolute removal" (Brown-Driver-Briggs Lexicon) or possibly "for Azazel" (some modern versions taking the term as a name) and outcast in the desert as part of the ceremonies of the Day of Atonement, that began during the Exodus with the original Tabernacle and continued through the times of the temples in Jerusalem.
Throughout the year, the sins of the ancient Israelites were daily transferred to the regular sin offerings as outlined in the Torah in Leviticus Ch 16. Once a year, on the tenth day of the seventh month in the Jewish calendar, the Day of Atonement, the High Priest of Israel sacrificed a bull for a sin offering for his own sins. Subsequently he took two goats and presented them at the door of the tabernacle with a view to dealing with the corporate sins of God's people — the nation of Israel. Two goats were chosen by lot: one to be "The Lord's Goat", which was offered as a blood sacrifice, and the other to be the "Azazel" scapegoat to be sent away into the wilderness. The blood of the slain goat was taken into the Holy of Holies behind the sacred veil and sprinkled on the mercy seat, the lid of the ark of the covenant. Later in the ceremonies of the day, the High Priest confessed the sins of the Israelites to Yahweh placing them figuratively on the head of the other goat, the Azazel scapegoat, who "took them away" never to be seen again. The sin of the nation was thus "atoned for" (paid for) by the "The Lord's Goat" and "The Azazel Goat".
In Christianity this process prefigures the sacrifice of Christ on the cross through which God has been propitiated and sins can be expiated. Jesus Christ is seen to have fulfilled all of the Biblical "types" - the High Priest who officiates at the ceremony, the Lord's goat that deals with the pollution of sin and the scapegoat that removes the "burden of sin". Christians believe that sinners who own their guilt and confess their sins, exercising faith and trust in the person and sacrifice of Jesus, are forgiven their sins.
Seventh-day Adventist Christians understand this symbolism differently. As the Azazel Goat was traditionally understood by Jews of antiquity [13] and Christians of the reformation [14] to represent Satan, Seventh-day Adventists' views harmonize with those of the reformation time period. (See Azazel for detail of this view.)
Since the second goat was sent away to perish,[15] the word "scapegoat" has developed to indicate a person who is blamed and punished for the sins of others.