"And ye shall be holy men unto me: neither shall ye eat any flesh that is torn of beasts in the field; ye shall cast it to the dogs." - Exodus 22:31 ( KJV )

This is only the second time we have encountered the term "Holy" in the - first and formal Law - given to Israel. Can you think back and recollect where and in what context it was first used? Take a moment to do that before you read on right now....

Here is the first occurrence - Its the 4th Commandment! "Remember the sabbath day, to keep it holy." Exo 20:8. There, the word was used to refer to a day that was - dedicated, sanctified, blessed, consecrated, set apart, and uniquely devoted - to Him. Here, we see it formally applied to the PEOPLE of Israel for the very first time in the Law. Gods people are commanded to be all those things to Him!
This concept - that Gods chosen people are set apart, separate and dedicated wholly to Him - was spoken before the Law was given, is a key component of later ordinances, and is a concept that goes all the way through and into the New Testament. The linkage of holiness to food here, is also highly significant - why on earth would holiness/consecration be linked with diet? Let's take a deeper look...
The whole intent of redemption (from Egypt and Sin) is for the Lord to have, out of all the people of the earth, a holy/separate nation of priests. (A priest = person who represents, and speaks on behalf of the people to God , as opposed to a prophet = person who represents and speaks on behalf of God to the people).

Before giving the Law, this was made clear to Moses and Israel. "And Moses went up unto God, and the LORD called unto him out of the mountain, saying, Thus shalt thou say to the house of Jacob, and tell the children of Israel;Ye have seen what I did unto the Egyptians, and how I bare you on eagles' wings, and brought you unto myself. Now therefore, --- if ye will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people: for all the earth is mine: And ye shall be unto me a kingdom of priests, and an holy nation. --- These are the words which thou shalt speak unto the children of Israel. And Moses came and called for the elders of the people, and laid before their faces all these words which the LORD commanded him. And all the people answered together, and said, All that the LORD hath spoken we will do. And Moses returned the words of the people unto the LORD." - Exo 19:3-8;

You can see the objective (priesthood) and the condition (obedience and covenant keeping) clearly outlined here,and please also note that the word Holy ( as in holy nation ) is used here BEFORE the Law was given. We see it repeated again further ahead in the Law as well ... " For I am the LORD that bringeth you up out of the land of Egypt, to be your God: ye shall therefore be holy, for I am holy." - Lev 11:45, also in Lev 19:2.
This has not changed under the New Covenant!

" But you are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you out of darkness into His marvelous light;" - 1 Peter 2:9, and again, " But as he which hath called you is holy, so be ye holy in all manner of conversation; --- Because it is written ---, Be ye holy; for I am holy." - 1 Peter 1:15-16. It is written!
We are to be in the world, but are to be distinct and separate from the world in our actions and our behavior- just as our Creator is everywhere present in the world but is separate and distinct from it, and His thoughts and actions are not as the worlds thoughts and actions. He loves the sinner, is faithful even though we are faithless, sends His rain on the just and unjust, and shows grace and mercy by redeeming those who once dwelt in darkness and even may have hated Him!

Holiness does not mean better than thou. It does not even mean clean, though cleanliness is an attribute of things meant to be dedicated to Him. The word sacred parallels it - as it denotes something uniquely separate and distinct from everything else. Ultimately though, holiness is an attribute of divinity itself ( "I am Holy" ) that is communicated to, shared with, attained, and reflected by, the people of God through uniting with, living with, and becoming like, Him. This is the process of Sanctification (cleansing for the purposes of setting apart for His service) which He is working in our lives for the ultimate aim of glorifying us with Him!
This separate-ness was constantly reinforced to the house of Israel in their day to day lives, through the dietary, hygiene and cleanliness requirements of the Law. They ensured that the Israelites were distinct from those nations around them.

Included in those restrictions was a prohibition on drinking blood. Interestingly, this restriction was one that was also enjoined on Gentile believers by the Holy Spirit and the Apostles. ( Acts 15:28-29 ), and here is where we see the linkage between holiness and diet.

Blood is Holy!

It is treated as separate and dedicated for the atonement of the people. " And whatsoever man there be of the house of Israel, or of the strangers that sojourn among you, that eateth any manner of blood; I will even set my face against that soul that eateth blood, and will cut him off from among his people. For the life of the flesh is in the blood: and I have given it to you upon the altar to make an atonement for your souls: for it is the blood that maketh an atonement for the soul. (Le 17:10-11). Here is the clearest picture given to Israel of the way to atonement and redemption. The penalty is also extremely severe for violation of this holiness. God will set His Face against that soul, and the soul will be cutoff from the people! This is worse than death!!!!! The Rabbi's uniformly agree that blood is not to be eaten because (a) it contains life (b) it is part of an offering that is dedicated to God! In other words, it is Holy to Him! Blood has been set apart for the specific reason of making atonement! What a wonderful picture of Christs work on the cross! (All the sacrifices in the book of Leviticus speak of the person of Christ, His Atonement, and present a picture of Him to His people so that they could understand and recognize Him and His Work when He appeared.)

This is probably one of the reasons for not eating an animal that has been killed by beasts in the field. The blood would not have all been drained out. Eating this flesh would cause the eater to be ritually unclean until the evening. The eater was to bathe himself and wash his clothes with water ( Lev 17:15-16 ). Obviously, this would also prevent the people from catching diseases like rabies etc.
The only blood that we are to partake of is the blood of His Son which does not merely contain Life ( another divine attribute ) but brings us into eternal fellowship with Him who IS Life. --- "Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you. Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day. For my flesh is meat indeed, and my blood is drink indeed. He that eateth my flesh, and drinketh my blood, dwelleth in me, and I in him. As the living Father hath sent me, and I live by the Father: so he that eateth me, even he shall live by me." - John 6:53-57

This was a hard saying for an observant Jew to stomach, but Christ was speaking of the sacrament of Communion that He was preparing to give His church. It is noteworthy that in those passages of the Last Supper in the Gospels that He does not say - this bread symbolizes my body or that this wine symbolizes my blood - He says it IS His Body and Blood.

This is the origin of the Catholic doctrine of Transsubstantiation - that the Communion wafer and wine are actually changed into the blood and flesh of Christ at some point during the Mass. Regardless of doctrine or when it happens, it is clear through our Lords own words,that through the sacrament of Communion, we are brought into physical contact with Him in a very real, practical, and meaningful way. It reminds and shows forth His death and resurrection, but it also unites us with Him in a very tangible way - (involving all our senses!) - making us partakers of His Holiness.

" Be Ye Holy" - is not just a command to His people. Like the words that called forth Light into existence, and created the sun, moon and stars - it is an expression of the sovereign, efficacious and unoverridable Will of God that decided to create humanity, and then from all created nations , elect and redeem a nation to Himself for eternal service to Him and the rest of humankind. Having said it, He is the One who will make it happen! ( "For this is the will of God, even your sanctification...."- 1 Thess 4:3)

" But we are bound to give thanks alway to God for you, brethren beloved of the Lord, because God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth: Whereunto he called you by our gospel, to the obtaining of the glory of our Lord Jesus Christ." - 2 Thess 2:13-14

Hallelujah!!