Leviticus 15:16

And if any man's seed of copulation go out from him
Not in lawful cohabitation, nor voluntarily, but involuntarily, as Aben Ezra observes; not through any disorder, which came by an accident, or in any criminal way, but through a dream, or any lustful imagination; what is commonly called nocturnal pollution ^F3; then he shall wash all his flesh in water, and be unclean until the
even;
and so the Egyptian priests, when it happened that they were defiled by a dream, they immediately purified themselves in a laver ^F4 so the Jewish priests did when the like happened to them asleep in the temple ^F5; see ( Deuteronomy 23:10 Deuteronomy 23:11 ) .