For the bread of God is that which cometh down out of heaven, and giveth life to the world. It is debated whether the ὁ καταβαίνων is "he who cometh down," or "that (bread) which cometh," etc.—whether in this verse the Lord passes at once to the identification of himself with the bread, or for a moment longer is delaying the announcement, and broadly asserting the qualities of that "bread of God," viz.
that whoever and whatever it is, IT comes from heaven, and gives life, not merely to the theocratic people, but to the whole world. (The latter is the view of Hengstenberg, Lange, Meyer, Westcott, Moulton; the former translation is partially urged by Godet, who thinks our Lord here spoke amphibologically, meaning both ideas, but by the form of the expression reserving the solution of the problem.
) It certainly does not follow that, if he was speaking of himself, the expression ὁ καταβάς would have been used, because, in John 6:50, after he has removed all ambiguity, he still uses the present tense, ὁ καταβαίνων.
The present tense is that of quality rather than of time. These characteristics of the veritable bread of God must hold good. It must have a heavenly origin, life-giving power, and universality of application to human need.
John 3:16 is here repeated. The whole world is the object of the Divine grace and love. The bread of God must be a Divine gift, mysterious and heavenly in its origin, and must at once demonstrate its vitality, its Source, and its Giver.