“He does this not only once but a second time, in order that we should know His strength. This strength by which He feeds the multitudes when He wishes and without bread finds its source in His divinity. He does this in order to bring them to believe that He Himself is the One who earlier had fed Israel for forty years in the wilderness.
And Jesus not only fed them with a few loaves of bread, but He even produced a surplus of seven baskets, so that He might be shown as incomparably surpassing Elijah, who himself also caused a multiplication of the widow’s small quantity of oil and flour (1 Kings 17:8-16).
Nevertheless, when Jesus produced a multiplication of seven baskets from seven loaves, He did not go beyond what was needed, lest the difference between these miracles should again be forgotten by the disciples.”
Theodore of Heraclea (c. 355) in Fragmenta in Mattheaum 98. MKGK 84.