51. In the first passage, Jesus, by recalling the effect previously produced, gives us clearly to understand that he was not acting with material bread; otherwise the comparison which he established with the yeast of the Pharisees had been without object. “Don’t you remember the five loaves for the five thousand, and how many basketfuls you gathered? Or the seven loaves for the four thousand, and how many basketfuls you gathered? How is it you don’t understand that I was not talking to you about bread? But be on your guard against the yeast of the Pharisees and Sadducees.” This reproach was given them for having had a material idea of the multiplication. The act had been extraordinary enough in itself to have struck the imagination of his disciples, who however appeared not to have remembered it.
This idea is set forth no less clearly from the speech of Jesus upon the bread from heaven, or manna, in which he tries to make them comprehend in the true sense the value of spiritual nourishment. “Work,” said he, “not for food that spoils, but for food that endures to eternal life, which the Son of Man will give you.” This nourishment is his word, which is the bread descended from heaven, and which gives life to the world. “I am the bread of life,” said he: “he who comes to me will never go hungry, and he who believes in me will never be thirsty.”
But these distinctions were too subtle for these rough natures, who could comprehend only tangible things. The manna which had fed their ancestors was the true bread from heaven to them: there was the miracle. If, then, the act of producing bread had taken place materially, why should these same men, for whose profit it was produced a few days before, say to Jesus: “What miraculous sign then will you give that we may see it and believe you? What will you do?” It is evident they understood miracles to be the mighty works which the Pharisees demanded; i.e., signs from heaven as commanded with the wand of an enchanter. Those which Jesus did were too simple, and did not depart enough from the laws of nature. The cures even were not sufficiently extraordinary. The spiritual miracles were not material enough for them.