For the life of the flesh is in the blood, and I have given it for you on the altar to make atonement for your souls, for it is the blood that makes atonement by the life.
Someone or something had to die when sin entered the world. Human beings lost a lot in that transgression. God made it clear to the Israelites that they needed to remember the cost of sin with the regular sacrifice at the altar. And this also affected certain dietary restrictions. To remember the cost of sin meant not eating the blood of any animal ever. It meant practicing a form of slaughter that drained as much blood from the animal as possible. All this was meant to show a regular appreciation for the atonement that took place at the altar. A calloused view of blood meant a disregard for relationship with God.
This prohibition was important enough that it was the one thing about the Old Testament Law that the early church felt compelled to remind Gentiles. All people should respect that blood is offered in atonement of sin (Acts 15:20). That regular reminder in the Jewish diet was really a form of regular worship. It acknowledged that sinners needed a sacrifice.
I see the wisdom in that reminder, and it is one reason why the New Testament church should at least regularly observe the Lord’s Table. It is in the symbols of the bread and the wine that we remember the cost of our sin, the sacrifice of our Savior, and the blood that was shed for the remission of sin. My sin is a costly mess. It literally cost God the ultimate sacrifice. Regularly remembering that is healthy for my soul.