John Calvin Commentary Matthew 16:8

"And Jesus perceiving it said, O ye of little faith, why reason ye among yourselves, because ye have no bread?" — Matthew 16:8 (ASV)

Why do you think within yourselves, etc.? The disciples again show how little they had learned from the instructions of their Master and from his wonderful works. What he had said about being on their guard against the leaven is rashly interpreted by them as if Christ intended only to withdraw them from social interaction. As it was customary among the Jews not to take food in company with ungodly people, the disciples imagine that the Pharisees were classed with such persons.

This ignorance might perhaps have been tolerated; but they are forgetful of a favor they recently received. They do not consider that Christ has the remedy—his power—to prevent them from being compelled to pollute themselves with food and drink. Therefore, he rebukes them sharply, as they deserved.

And certainly, it was shameful ingratitude that, after having seen bread created out of nothing, and in such abundance as to satisfy many thousands of people, and after having seen this done twice, they are now anxious about bread, as if their Master did not always possess the same power.

From these words, we infer that all who have once or twice experienced the power of God and distrust it for the future are convicted of unbelief. For it is faith that nurtures in our hearts the remembrance of the gifts of God, and faith must have been lulled to sleep if we allow them to be forgotten.