Sacrifice of animals dates back to earliest times; it was practiced, for
example, by Abel (Gen.4:4) and Noah (Gen.8:20). The Jewish sacrificial
laws are detailed in the first seven chapters of Leviticus. These laws
were in effect until the Second Temple was destroyed by the Romans in 70
C.E. They are no longer operative because, ever since the Temple was first
built by Solomon (1 Kings 5ff), sacrifice outside the Temple has not been
permitted (see, e.g., Lev. 17:1-7).
G-d found the sacrifices of both Abel and Noah
appropriate, but as the Bible tell us repeatedly
G-d wants righteousness and repentance, not sacrifice.
Verses on this topic include 1 Samuel 15:22,
Psalms 51:17, Hosea 6:6, etc. In his Guide for the
Perplexed (III:32) Maimonides explains that the
Torah requires sacrifices because that was the
expected form of worship in those days. One of
the Rabbis of the Talmud used to say that fasting,
which diminishes a person's fat and blood, should
be even more effective than offering the fat and
blood of a sacrifice on the altar (Berachos 17a).
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