Participation in Jesus' flesh and blood is described as necessary for life and abiding union.

John 6:53–56

⁵³Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you.

⁵⁴Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day.

⁵⁵For my flesh is meat indeed, and my blood is drink indeed.

⁵⁶He that eateth my flesh, and drinketh my blood, dwelleth in me, and I in him.