No explanation is given for the prohibition.
We are simply told that an Israelite may not eat blood. It must be poured on
the ground “like water.” This specification seems to indicate that the blood is
simply to be disposed of; it is not to be accorded with the special treatment
it would receive in the cult. As von Rad puts it, “this pouring out of the
blood is definitely denied the character of a sacrifice (it is to be like
water.” (von Rad, Deuteronomy, 93) The prescription that the blood is to
be poured out “like water” points to the possibility of an alternative way of
dealing with the blood, that it would be treated other than “like water.” Thus,
the deliberate act of not doing anything with the blood except disposing of it
by pouring it out on the ground is ritualized activity, since it is strategically
distinguished from another assumed type of activity and a privileged position
is established. (William K. Gilders, Blood Ritual in the Hebrew Bible: Meaning
and Power [Baltimore, Md: The John Hopkins University Press, 2004], 15)