As to the text which seems to oblige Communion under both forms, it is a question of interpretation. The Catholic Church is the only authoritative interpreter of
Christ’s doctrine; to none other has this power been granted. Omitting here the many meanings Catholic theologians attribute to the verse, “Except you eat the flesh of the
Son of man, and drink his blood, you shall not have life in you” (John, vi, 54), it should be noted that
the Catholic Church has officially declared that these words do not make Communion under both forms obligatory (Denzinger-Bannwart, 930). This conclusion is substantiated by Scripture:
“If any man eat of this bread, he shall live for ever; and the bread that I will give, is my flesh, for the life of the world” (John, vi, 52). It is true that some theologians believe more grace is conferred by Communion under both forms. But this question is speculative, not practical. It does not affect the Church’s dogma, nor is this opinion by any means common to all Catholic theologians.