Christ was born in the flesh, had no sin, was crucified for the remission of sins of those who believe, and He was raised by The Father to sit on His right hand, expecting until all His enemies are made His footstool. Christ ended the need for a fleshy priesthood and fleshy sacrifices, and He became the Perfect Sacrifice for one and all time, our Passover sacrificed for us. Those who remain faithful in Him to the end are to rule with Him on the earth as priests and kings. Christ Jesus only is our Salvation, the only Way of Salvation, for there is no other name by which man can be saved.
All those things are about The New Covenant, and there's more than just that which show difference from the Old Covenant.
However, the Old Testament 'Books', ALSO include many prophecies specific to The New Covenant, which is why we as Christians should not slight our study in the Old Testament Books, especially those of the prophets as we are commanded to be mindful of.
Yes as far as the works of the Old Law compared to now, the differences are too numerous to mention.
But that is because the Old Law merely contain shadows of things.
For example we know that sheep pictured the meek people of this earth.
The spots on a lamb pictured sin in men.
A pure white lamb prefigured Christ.
All of the things in that law amplified that message of God about sin and our need of being cleansed to holiness.
The clean and unclean meats were about impressing that same point on us. The unclean meat represented unclean men.
The things under the Old Law were symbolism to illustrate spiritual points.
If it is actually harmful to eat all animals then God told Noah and his family to do what was harmful to them at Genesis 9:3-4.
God could have told them to eat just certain animals but he did not. That proves that God does not view eating them as bad in and of itself.
“Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things. But flesh with the life thereof, which is the blood thereof, shall ye not eat.”
God told them not to eat those things for a two-fold reason:
(1) To demonstrate that he is the law-giver and he has the right to ask us to do what-ever he desires.
(2) The unclean meats pictured spiritually unclean men. That is why men and nations are compared so often to beasts in the OT.
Just as we are asked to eat Jesus’ body, our clinging to a friend and adopting that friend’s ways is like eating him, assimilating him in our self. That is why bad association spoils useful habits. 1 Corinthians 15:33 "Be not deceived: Evil companionships corrupt good morals." (ASV)
Peter knew the unclean animals pictured spiritually unclean humans. Read: Acts 10: 9-28
There is much difference in that regard which one does not see unless they meditate in that law with the aide of the holy spirit.
But those that do understand what the various utensils and all those things under that Old Law prefigured, they also understand that it is nothing but progress to something better that we no longer live by those things of that Old Law.
And they understand that God has not changed. He is the same yesterday, today, and tomorrow His grace is who he is. It is a part of his love and as 1 John 4:8 says, "God is love."
