The prohibition of eating meat taken from the body of an animal whilst
alive is based on the words אך בשר בנפשו דמו לא תאכלו “But flesh,
when the blood thereof is in its soul, shall ye not eat” (Gen. ix. 4).
The phrase “to be in the soul” means to be surrounded and animated by
the soul, to be in the midst of active, living organs of the animal.
“The blood of an animal is in the soul thereof” may therefore be
paraphrased thus, “The blood hath its vital powers and the animal is
alive.” (Comp. Lev. xvii. 11.)
This prohibition is one of the שבע מצות בני נח “the seven Noachide
commandments,” i.e., commandments which, according to Tradition, were
already in force in the days of Noah, and are binding on all his
children or all mankind, and not on the Israelites alone; viz., (1) the
prohibition of idolatry (עבודה זרה), (2) of murder (שפיכות דם), (3)
of adultery (גלוי עריות), (4) of blasphemy (ברכת השם), (5) of
robbery (גזל), (6) of eating meat taken from a living animal (אבר מן
החי), and (7) the institution of courts of justice (דינין). See
Babyl. Talm., Sanhedrin 56a.