Reuben heard
Genesis 35:22
And it came to pass, when Israel dwelt in that land, that Reuben went and lay with Bilhah his father's concubine: and Israel heard it. Now the sons of Jacob were twelve:
Genesis 42:22
And Reuben answered them, saying, Spake I not unto you, saying, Do not sin against the child; and ye would not hear? therefore, behold, also his blood is required.
not kill him
Joshua 10:28
And that day Joshua took Makkedah, and smote it with the edge of the sword, and the king thereof he utterly destroyed, them, and all the souls that were therein; he let none remain: and he did to the king of Makkedah as he did unto the king of Jericho.
Genesis 9:5
And surely your blood of your lives will I require; at the hand of every beast will I require it, and at the hand of man; at the hand of every man's brother will I require the life of man.
Matthew 10:28
And fear not them which kill the body, but are not able to kill the soul: but rather fear him which is able to destroy both soul and body in hell.