‘And when they were filled he says to his disciples, “Gather up the broken pieces which remain over, that nothing be lost.” So they gathered them up, and filled twelve baskets with broken pieces from the five barley loaves which remained over to them that had eaten.'
The people, well over five thousand, ate their fill and then twelve baskets full of remains were gathered up at Jesus' command. Presumably each of the twelve had a basket. John specifically states that what remained was the remains of the five barley loaves, just as he had previously stated that they ate of them and the fish as much as they would. Thus he saw the ‘sign' as a miracle of great magnitude. Nothing gatherable would have been left of the fishes except traces on the loaves, nor would they remain edible. They were better left for the birds. The gathering up of the remnants is a reminder of the poverty of those days. They would be available for the people to take way with them and must not be wasted. Once again we are aware of the memories of an eye-witness.
We may well be intended to see the mention of the numbers as significant. Five was the number of the covenant, and twelve the number of the tribes of Israel. Thus the feast is a covenant feast, offering a place in God's covenant to all true believers (John 6:35), and there is sufficient to spare for all Israel. As with the wine at Cana we are to see that there was an abundance of provision.