It is a perpetual statute throughout your generations in all your dwellings: you shall not eat any fat or any blood.'" (Leviticus 3:17)
The literal commandment is that we are not to eat blood.
Messiah implicitly affirmed this commandment when He spoke about the Law:
"Do not think that I came to abolish the Law or the Prophets; I did not come to abolish but to fulfill. For truly I say to you, until heaven and earth pass away, not the smallest letter or stroke shall pass from the Law until all is accomplished. Whoever then annuls one of the least of these commandments, and teaches others to do the same, shall be called least in the kingdom of heaven; but whoever keeps and teaches them, he shall be called great in the kingdom of heaven. (Matthew 5:17-19)
Some have asked about Mark 7:19. Messiah was speaking of ritual impurity resulting from eating bread with unwashed hands. We recommend this detailed study of that passage if you have additional questions.
G-d created the heaven, the earth, the sea and everything that is in them. (Psalm 146:6) He did so with an intended structure and order. Part of that intended order was that certain animals were created for food and other animals were not. This was recognized from the beginning even as early as Noah's time. He recognized the difference between clean and unclean animals. (Genesis 7:2-9). G-d also specified that certain parts of animals were unsuitable for food, blood being one of those parts.
In a similar manner, there is a certain individual in G-d's order who would save the world from sin: the Messiah Yeshua. There is no other person intended for that purpose. Attempting to find salvation in anyone (or anything) else is akin to eating blood or marrying your sister: G-d says 'no'.
G-d tells us "the life of the flesh is in the blood". We are to find life in Messiah alone and not in the blood of bulls, goats, or other animals. It is impossible for them to provide life the way Messiah alone can.
We know that Messiah did not sin (Hebrews 4:15) and so we know Messiah fulfilled this commandment by not eating blood.
Traditional observance of this commandment is found in its literal sense: not eating blood.
There are numerous, detailed stringencies traditional Judaism has added to the process of slaughtering and preparing animals for consumption to ensure as little blood as possible is present in the meat.
We are able to fulfill this commandment today and should not eat blood.
This does not mean, however, that non-Jewish believers are required to take on all the traditional Jewish stringencies of this commandment.