“By the Eucharist the community is integrated into the body of Christ. And the body is inseparable from the head. ‘The least separation would bring about our death,’ says John Chrysostom in another passage.
Just as the head and the body constitute a single human being, so Christ and the Church constitute a single whole.
This union is effected through the food that he has given us in his desire to show the love he has for us. For this reason he united himself intimately with us, he blended his body with ours like leaven, so that we should become one single entity, as the body is joined to the head. (John Chrysostom, Homily on 1Corinthians 30, 1, Homily on John 46, 3)
Let us learn the wonder of this sacrament, the purpose of its institution, the effects it produces. We become a single body, according to Scripture, members of his flesh and bone of his bones. This is what is brought about by the food that he gives us. He blends himself with us so that we may all become one single entity in the way the body is joined to the head. (John Chrysostom Homily on John 46)” (Clément, Olivier, The Roots of Christian Mysticism, pg 115)