Lets begin this discussion by looking at this Biblical passage:
9:1 And God blessed Noah and his sons and said to them, "Be fruitful and multiply, and fill the earth.
2 And the fear of you and the terror of you shall be on every beast of the earth and on every bird of the sky; with everything that creeps on the ground, and all the fish of the sea, into your hand they are given.
3 Every moving thing that is alive shall be food for you; I give all to you, as I gave the green plant.
4 Only you shall not eat flesh with its life, that is, its blood.
It is important for our understanding of this passage that we understand what took place in Genesis 8:20-22. (If you are not familiar with this passage and its intent, click on the link.)
This whole passage is a concession from God and does not express the will of God. God recognizes the evilness of the human heart and is allowing humankind to live in a state of being that is less than His desire or ideal.
The whole point of this concession, and the fact that it is a concession, is based upon the comparison to the actual perfect condition of the creation in Eden, in which there was no death prior to the Fall. Eden was a time when all were to be obedient to the will of God.
Following the Fall, the world began to become more and more corrupt until God said that there was no redeeming human quality left upon the earth, save in Noah, who walked with God (Genesis 6:5-9).
God's first concession was the granting of forgiveness to all who were truly repentant and truly desired in their hearts to go forth and sin no more. This is the redeeming quality that was apparently lacking in the people of the earth when God decided to destroy them.
So, Noah spent 120 years building an ark as a testimony against the people of the earth for their hardness of heart and disbelief. And during this time there was unrepentant killing upon the earth, as reflected in Lamech's statement (Genesis 4:23-24).
However, upon the ark there was once again no death, and apparent obedience to the Lord. But following the Flood, when there was supposed to be another Edenic way of peaceful living and obedience to God, Noah and his family sacrificed innocent animals, because they supposedly recognized themselves as not pure, and needed to repent. This brings about the mixed feelings of God, as expressed in Genesis 8:21.
Apparently, it is easier to kill an innocent animal than it is to be obedient to the Lord our God. Or, perhaps there is more to this corrupted state of being. Are humans expressing their dominance and power over the animals by killing and eating those who are weaker than themselves (The sin of the boastful pride of life)? Are humans expressing their sins of the lust of the flesh and the lust of the eyes (1 John 2:16), by eating the flesh that had been denied them as poor people who looked upon the eating of flesh as a status symbol? I believe the answer to both questions is, "Yes!"
Nevertheless, in the hope of their obedient return to His perfect will, once again God concedes to the imperfect human state, and proceeds to bless Noah and his sons (Genesis 9:1). Curiously, the passage does not say that God blessed Noah and his family, but only his sons. Could it be that the corruption upon the ark came about through the women?
For nearly a year, the animals upon the ark had lived in close confinement with Noah and his human family. It must have been as though these animals were also part of Noah's family. The killing of the innocent animals for the sacrifice was a betrayal of the pre-existing peaceful state, and brought fear and terror to the heart and soul of every animal upon the ark. This is the key point that God emphasizes and expands upon in Genesis 9:2. Not only had the humans lost their perfect state of being with God, but now they had lost the companionship and fellowship of most of the animal kingdom.
God, knowing the evilness of the human heart, further grants the concession of eating the animals, for He acknowledges that the humans are not ready to repent of their evil nature.
Today, many people compound this evilness by attempting to twist this concession into a commandment, and saying that God commanded them to kill and eat the flesh of animals. Nothing could be further from the truth! This can be clearly seen in the impossible condition stated in Genesis 9:4.
The word that is used in Genesis 9:4 for life is in reality "soul," נפש. In other words, humans were not to eat the animal until the soul, which is in its blood, had departed from the body. And, as every flesh eater and supermarket shopper has observed, it is impossible to remove all of the blood from the flesh.
Furthermore, I believe that God placed this impossible condition in verse 4 as a way of bringing us back to the reality of the evilness of eating the flesh of another being, that we would repent and once again become obedient to the heavenly will of God.
The Hebrew sages recognized this fact, too, for the Jewish people have no prayer of thanksgiving for flesh foods as they do for all plant foods.
It is clear that the eating of animals is a concession and not the will of God.