||Take seven pairs of every clean animal, each consisting of a male and its mate. Of every animal that is not clean, take two, a male and its mate.
Mikol habehemah hatehorah tikach-lecha shiv'ah shiv'ah ish ve'ishto umin-habehemah asher lo tehorah hi shnayim ish ve'ishto.
(Bereshith Rabbah; Radak, Malbim. See Genesis 7:9). Literally, 'seven by seven.' This is a detail not mentioned earlier in Genesis 6:19. Earlier, when the Torah uses God's name Elohim, which denotes justice, only two animals are mentioned. Accepting a sacrifice is an act of mercy, which pertains to God's name Adonoy (see commentaries on Leviticus 1:2). In the verse here, the name Adonoy is used, and seven pairs are required, the extra ones for sacrifice (Rashi). See Genesis 8:20.