Interpreting the Lord’s words in a literal sense, the disciples believed he was instructing them to abstain from the bread associated with the Pharisees, Sadducees, and Herodians to avoid contamination. They felt that having only one loaf was a reflection of their oversight and negligence. They then murmured among themselves, “We have no bread.” However, aware of their reasoning, the Lord confronted them about their lack of understanding and faith. As Blessed Theophylact pointed out, their foolishness was evident in their failure to remember how he had previously fed thousands with just a few loaves, and their disbelief stemmed from doubting his ability to provide for them again, despite having no bread.
“Why do you think within yourselves, O you of little faith, that you lack loaves? Do you not perceive or comprehend? Is your heart still hardened? Do you not see with your eyes and hear with your ears, and do you not remember?” He then posed the question, “When I broke five loaves for five thousand, how many baskets full of leftovers did you gather?” They replied, “Twenty.” “And when I broke seven loaves for four thousand, how many baskets of leftovers did you take?” They answered, “Seven.” “Why do you fail to understand that I was not speaking about bread but rather concerning the leaven of the Pharisees, Sadducees, and Herodians?”
At that moment, the witnesses of the miraculous multiplication of loaves realized that in the presence of their Master, their preoccupation with physical bread was misplaced and that he was warning them not against bread itself but against the teachings of the Pharisees, Sadducees, and Herodians.