What does Genesis 7:2 mean?
In the previous verse, God instructed Noah and his family to enter the ark. They are to take with them the animals, and here additional creatures are added. Specifically, they must bring seven pairs (male and female) of the clean animals and one pair each of the unclean animals. The first readers of Genesis would likely have understood what was meant by clean and unclean animals, but this is the first hint in Scripture that God had designated some kinds of animals as clean and others as unclean.Why seven pairs of the clean animals? After the flood, Noah will offer animal sacrifices to God (Genesis 8:20). Only clean animals are acceptable as a sacrifice, and Noah will need more than just one pair of those if each kind of animal is to survive as a species.
We know from Genesis 6:20 that the animals Noah was to take on the ark would have come to him; he didn't have to go search for, select, and bring them back to the ark. However, Noah and his family were responsible to take them in with them. These last-minute preparations would have taken time (Genesis 7:4), and according to this chapter, Noah and his family complete their work just in time (Genesis 7:13).