Question: where does it say in the bible not to have a blood transfusion?
Answer: Doctrine. On the basis of various biblical texts, including Genesis 9:4, Leviticus 17:10, and Acts 15:28-15:29, Jehovah's Witnesses believe: Blood represents life and is sacred to God. After it has been removed from a creature, the only use of blood that God has authorized is for the atonement of sins.