So says Leviticus 17:11. Everyone knows that we must have enough blood flowing around our body or else our bodily functions deteriorate and we die. Yet for a long time the exact function of blood was little understood. In what ways has modern science shown Leviticus 17:11 to be true? Blood is fundamental to the function of every cell of every component in our bodies. Cells need food to survive, grow, repair themselves and to fulfill their specific functions, and, to reproduce.