The number of each “kind” that were to be brought on Noah’s Ark during the global flood is inconsistent within the Bible. The contradiction can be found between Genesis 6 and Genesis 7 when God is telling Noah the number of animals he is to bring. Furthermore, the passage in Genesis 7 is an anachronism in biblical chronology, because which animals are clean and which are unclean was only revealed in laws given to Moses after the exodus of Israelites from Egypt.
Biblical scholars have several different models for the origins of the Bible, including Genesis. One model is the documentary hypothesis, which holds that the Bible was assembled from multiple independent sources, each written centuries apart from the others, in a process of redaction. This means that one or more ancient Jews “spliced” different versions of different stories into one long book (or rather, five longish books), resulting in noticeable duplications and contradictions (such as the separate creation stories in Genesis 1 and 2, and of course, the issues discussed on this page). Another possibility is that the Bible did begin as a single narrative, and over the centuries various stories, rules, and commentaries were added and subtracted to it — rather like a wiki. Either way, it is believed that the command to bring seven pairs of clean animals was a later variation, added to the story so that Noah has some clean animals to sacrifice at the end without making them extinct.
And…..they wonder why they’ve lost all credibility outside of their own shitty, crumbling cults.