For the of the is in the bloodThe other is in John 6:54
Whoso eateth my , and drinketh my , hath eternal lifeAs mentioned before, the consumption of blood was prohibited under the Law of Moses. It was regarded as the lifegiving substance of man and something sacred. As stated in Leviticus, it gives life to the flesh. Thus, the Jews were upset when Jesus told them, contrary to their law, to drink his blood. Why would he ask them that? Because his blood gives life to the spirit. Our blood gives mortal life, his blood gives eternal life.
This topic seems to be a source of irony and paradoxes in the scriptures. Compare what we read about Captain Moroni in Alma 48:13
Yea, and he was a man who was firm in the faith of Christ, and he had sworn with an oath to defend his people, his rights, and his country, and his religion, even to the loss of his blood.
...with what we read about Amaleckiah in Alma 49:27
Yea, he was exceedingly wroth, and he did curse God, and also Moroni, swearing with an oath that he would drink his bloodI don't think these parallels are a coincidence. I think it's a carefully crafted text by Mormon, perhaps aided by what was already written on the Plates of Nephi that he abridged from.
Moroni was willing to sacrifice his blood for this just cause (a type of Christ?). Amaleckiah was the antitype, who sought not only to take Moroni's life but also consume his lifegiving substance, the blood. The irony is topped off by the death of Amaleckiah shortly after. As Tyler Griffin points out here.
Once again I don’t want to make you sick, but Amalickiah had sworn with a wrathful oath that he was going to drink Moroni’s blood. Brothers and sisters, the last thing Amalickiah would have done in mortality, laying there in his sleep as a javelin pierces his heart and lung—would have caused blood to pool up, as he’s laying down, in his throat—the very last thing Amalickiah would have done in mortality would have been choke on and drink his own blood.