Genesis 7:2
“Of every clean beast thou shalt take to thee by sevens, the male and his female: and of beasts that are not clean by two, the male and his female.”
KJV
Read in Genesis 7Meaning
The verse distinguishes clean and not-clean animals and gives Noah different numbers to bring into the ark.
Read carefully
The clean/unclean distinction appears here before Sinai; the verse does not itself explain a complete later dietary law system.
Reflection
The preservation plan is detailed enough to serve purposes that become clearer as the narrative continues after the flood.