The verse is taken to contradict Genesis 7:2 which says 7 of every clean kind. But the verse probably refers to the overall act of bringing a pair, or in absolute terms, at least a pair of every living thing (there wouldn’t be that many clean animals anyway). The point of the verse is to describe that a male and a female will be brought, saving the species, and not as to exactly how many pairs will be brought. Therefore, Genesis 7:2 is more specific in a certain area. This is supported by the fact that Genesis 7:2 says 7 pairs, male and its female, which is probably the author’s two by two in Genesis 7:9,15.
