John Gill Commentary John 6:13

"So they gathered them up, and filled twelve baskets with broken pieces from the five barley loaves, which remained over unto them that had eaten." — John 6:13 (ASV)

Therefore they gathered [them] together
The several broken bits of bread, which lay about upon the grass, which the people had left, after they had been sufficiently refreshed:

and filled twelve baskets ;
every disciple had a basket filled:

with the fragments of the five barley loaves ;
and it may be of the fishes also:

which remained over and above unto them that had eaten ;
such a marvellous increase was there, through the power of Christ going along with them; insomuch that they multiplied to such a degree, either in the hands of the distributors, or of the eaters.