John Gill Commentary Genesis 7:9

"there went in two and two unto Noah into the ark, male and female, as God commanded Noah." — Genesis 7:9 (ASV)

There went in two and two unto Noah into the ark Of themselves, as Jarchi and Aben Ezra, being impressed with an instinct from God so to do; or by the ministry of angels, as observed (See Gill on Genesis 6:20) there were two of a sort, and some think four:

the male and the female ; and of some seven, or seven pairs, as before observed:

as God commanded Noah ; which respects his own and his family's entrance and the creatures; both were commanded by God, and attended to by Noah, who was obedient in all things.