The Lord had already said in Genesis 6:1–22 that a pair of every species of animal needed to be brought along. The purpose of it was for each species to remain in existence on earth. God now added something to this. He ordered that every species of animal that was clean was to be represented with seven pairs. In Genesis 7:7 we read that this also included species of birds that were clean and used in the sacrificial service.
Why was this done? Because some of the animals that were clean were to be sacrificed when the earth was dry again. If only one pair of the clean animals were taken, it would mean that after the first sacrifice, that species of animal would have been extinct. The Lord intended for wildlife to continue in all its variation.
It is remarkable that Noah knew which animals were clean or unclean. We are not given a list of clean and unclean animals in the first six chapters of Genesis. In fact, we do not read about this until Leviticus 11:1–47. From this, among other things, you can see that the children of God knew much more in the early days than what we read in the first part of the Bible. God had told them much more than what we read in the Bible about that time. The knowledge and substance of their faith was much broader than the content of what we are told in the Bible about that time.
2 Take with you seven pairs of all clean animals, the male and his mate, and a pair of the animals that are not clean, the male and his mate,