The standard Christian teaching is that God’s covenant with Noah required the shedding of human blood, but this is misleading. After giving Noah permission to eat the plants and animals that grow on earth, God said that humans should not eat meat with blood in it (Gen 9:4). There were good health reasons for this command, because meat which has not had the blood drained from it will spoil quickly in the heat and go rotten.
Genesis 9:5-6 goes on to speak about the blood of humans. I have given a very literal translation.
The blood of your life
I will require
from the hand of every animal.
I shall require it
from the hand of the human
his brother
I shall require
the life of the human.
The one shedding the blood of a human
His blood shall be shared,
because he made him in the image of God.
These two verses are used to justify the death penalty for murder, but the passage has several problems.
First of all, the word usually translated as “require” is “darash”. Its basic meaning is tread or to frequent, and thus to seek or inquire. Require is not the usual meaning of the world. Most translators assume that inquire or frequent would not make sense, so they use “require” instead. I wonder if the word “inquire” is used because the spiritual powers of evil are inquiring or demanding a right from God.
These verses also stand out because they have a chiliastic format common in Hebrew poetry. Ideas are expressed forward and backwards, using the same words.
These words are not God’s standard. He loves life and does not take lives, unnecessarily. God does not want blood to be shed to pay for a person killed.
He established the penalty of community exclusion, not a death penalty. If the excluded person leaves freely, blood will not be shed.
God established a process by which the victims family request a ransom from the murderer, instead of excluding. God allowed this, so he did not demand blood.
The last phrase said that he created humans in the image of God implies that God is not speaking.
I believe that these two verses could be the spiritual powers of evil speaking; possibly through Noah perhaps without him realising. They demanded blood for anyone who died. If a person was murdered, they lost a slave. They would demand the payment of the of another slave, even though it made them worse off. This was their warped way of thinking. They love so much they will do anything to get it, even if it harms them. This was not God speaking.
God granted this concession to the spiritual powers of evil, because he had no choice. Humans had placed themselves in their power by disobeying God and submitting to them. Humans had not paid the ransom that the spiritual powers of evil demanded, so he had to concede to their demand, but he did not approve.
Gen 9:5-6 was a concession to the spiritual powers of evil, not a command to humans. It was a statement of the current reality, not a command to implement the death penalty.
The uncertainty about the meaning of these verses means that we should be careful about using them as a basis for a claim that God requires blood from humans who sin. They should not be used as the basis for the death penalty.