There is no return from exile unless transgression is undone. Any attempt to return to the garden without a blood atonement cheapens the transgression. It’s like a man who turns from a whore to kiss his wife. The affront is as vile as the infidelity. His wife should vomit in his mouth.
A sword then – precisely because swords shed blood. Any return to paradise, the place where God and man were married, requires blood, because their union had been as real as could be.