John Chrysostom

Wherefore also He works another miracle, and then and not till then He reproves; I mean, He brings forward what they were reasoning in their hearts. But what were their reasonings? "Because," so it is said, "we have taken no bread." For as yet they were full of trepidation about the purifications of the Jews, and the observances of meats.

Homily on the Gospel of Matthew 53 ↗

Theophylact of Ohrid

And they reasoned among themselves, saying, It is because we have taken no bread. But Jesus, aware of this, said unto them, O ye of little faith, why reason ye among yourselves, because ye have brought no bread? Do ye not yet understand, neither remember the five loaves of the five thousand, and how many baskets (kophinoi) ye took up? Neither the seven loaves of the four thousand, and how many baskets (spyridas) ye took up? …

Commentary on Matthew ↗

Thomas Aquinas

Consequently the understanding of the disciples is set forth: but they thought within themselves etc. For since above they had received seven baskets of fragments, and had not brought them along, they believed that he was saying, you did not take bread; but I do not want you to accept bread from the Pharisees, because they were sensual, and the sensual man perceiveth not these things that are of the Spirit of God, 1 Cor. 2:14.

Commentary on Matthew ↗