God has made it clear not to eat blood. I'll put a few old testament examples for reference.
Genesis 9:4 KJV
But flesh with the life thereof, which is the blood thereof, shall ye not eat.
Leviticus 7:26 KJV
Moreover ye shall eat no manner of blood, whether it be of fowl or of beast, in any of your dwellings.
1 Samuel 14:32-33 KJV
And the people flew upon the spoil, and took sheep, and oxen, and calves, and slew them on the ground: and the people did eat them with the blood. [33] Then they told Saul, saying, Behold, the people sin against the Lord , in that they eat with the blood. And he said, Ye have transgressed: roll a great stone unto me this day.
In the new testament we learn that some were told that they must take the circumcision, but it was not so. We learn in Acts 15 what things are necessary for the gentiles.
Acts 15:28-29 KJV
For it seemed good to the Holy Ghost, and to us, to lay upon you no greater burden than these necessary things; [29] That ye abstain from meats offered to idols, and from blood, and from things strangled, and from fornication: from which if ye keep yourselves, ye shall do well. Fare ye well.
It is repeated to us that we should not eat blood, so this is something that is important for all Christians to know.
Is it okay to eat blood after it is cooked? If so, where is the biblical justification?
Some argue that eating a rare steak is eating blood, and therefore eating it is a sin. If the steak is cooked longer, where does the blood go? If there is blood in the meat, it seems that we shouldn't eat it at any temperature.
My understanding is that myoglobin is a protein that causes red meats to have their red color. As the protein is heated, it is denatured and changes color.
I am willing to be corrected on this issue and look forward to the discussion.