In Deuteronomy 14 and Leviticus 11 God has provided us with a detailed list of clean and unclean animals according to the mind of God. God instructed Israel to follow through with this list and to not eat any animals considered by God to be unclean.
One of the perceptions of the spiritual walk is that many consider he clean and unclean laws to have been presented only to Israel as part of the Old Covenant. Therefore these people believe that there were no laws from God regarding as to whether we should eat certain animals before Mt. Sinai. Many people, since there are no specific mention of the precise structure of the laws Abraham had obeyed in Genesis 26:5, believe that there was no such thing as clean and unclean animals before Mt. Sinai.
In Genesis 7:1-3 God says the following:
“And the Lord said unto Noah, “Come thou and all thy house into the ark; for thee have I seen righteous before Me in this generation. Of every clean beast thou shalt take to thee by sevens, the male and his female: and of the beasts that are not clean by two, the male and is female. Of fowls also of the air by sevens, the male and the female; to keep seed alive upon the face of all the earth.”
This Scripture clearly states that the principles of clean and unclean animals was in effect long before Mt. Sinai and the writing of Deuteronomy and of Leviticus. This also lends credence to the concept that the laws that God gave Abraham must have had this concept included in the laws, precepts, and commandments that God gave Abraham.
In Genesis 8:20 God says the following:
“And Noah builded an altar unto the Lord; and took of every clean beast, and of every clean fowl, and offered burnt offerings on the altar.”
The concept of clean and unclean animals and birds is restated and the 7th bird, or animal, is brought to the altar to be sacrificed. Thus again the concept of clean and unclean appears to be have been a common thought in the days of Noah. Thus by extension this same principle will be in effect in the time of the end, “But as the days of Noe were, so shall also the coming of the Son of man be?” Matthew 24:
God wants us to be firmly grounded on the truths that He has chosen to reveal through His agencies and when as well. God knows how many of His truths were already known to His people. We know that the sacrificial system was in place before Mt. Sinai. We know that Cain and Abel were participants in a communal form of worship thus requiring certain rules and regulations that people need in order to conduct public worship systems. We also know that the ten-commandment law was already in place including the Sabbath commandment.
So it appears that with the clean and unclean animal system at the very least, the general outline of the Jewish worship system was intact and active before Mt. Sinai. This shows that God is the same yesterday, today, and forever, and that the principles of His worship system are also the same. Let us grow in grace and truth and trust in His Word and in His principles – as Noah did.