Looking at the huge crowd gathered to hear him, Jesus asks his disciple Philip where they could possibly find enough food to feed the large crowd. As happens often in John’s Gospel, Jesus knows exactly what he is about to do so this question is a test for the disciples (John 6:6). Marianne Meye Thompson acknowledges the verb used here can refer to a temptation or trap, but in this cases it is better “examine, try, prove” (John, 140).
Another disciple who is only mentioned in the Synoptic gospels, Andrew, finds a boy with a small lunch. Andrew probably did not think the food could be shared, he was pointing out the impossibility of finding enough food for the crowd. The fish were probably small pickled fish (not a sardine, but something similar). No one would carry a pair of rainbow trout in their satchel on the outside chance they were needed to feed a crowd!
Jesus takes this small amount of food, offers thanks, and then distributes the food to the crowd. The crowd sees that is a miracle and wonder what kind of prophet Jesus is. They have in a mind a tradition drawn from Deut 18:15-18 that another prophet like Moses will come into the world. Moses fed the Israelites manna in the wilderness, in a similar way Jesus gives bread to a new Israel in a new wilderness.
Deuteronomy 18:15-18 (ESV) “The LORD your God will raise up for you a prophet like me from among you, from your brothers—it is to him you shall listen— 16 just as you desired of the LORD your God at Horeb on the day of the assembly, when you said, ‘Let me not hear again the voice of the LORD my God or see this great fire any more, lest I die.’ 17 And the LORD said to me, ‘They are right in what they have spoken. 18 I will raise up for them a prophet like you from among their brothers. And I will put my words in his mouth, and he shall speak to them all that I command him.
It is possible this miracle is an allusion to Elisha (2 Kings 4:42-44). In 2 Kings the prophet Elisha feeds 150 men with a small amount of food. There are similarities, but the more important allusion is to the wilderness period of Israel’s history.
The food provides enough for all the crowd to eat until they are satisfied and still have twelve baskets left over. Consider these are poor people who are given free food and allowed to eat as much as they want. I think they probably overate and maybe stuffed a few leftovers in their pockets to take home to the family.
The point of the leftovers? “This is the ample provision of the Lord who declared, ‘My people will be filled with the bounty’ (Jeremiah 31:14)” (Carson, John, 271). Just as Jesus provided plentiful excellent wine at the wedding in Cana (John 2:1-12) and healed a man who was crippled for thirty-eight years (5:5-6), now Jesus provides enough food everyone is satisfied and there are plenty of leftovers. Like the wine at the wedding in Cana, Jesus is revealing for those who have ears to hear that he is the host of an eschatological banquet, like the manna in the wilderness God is providing new bread for his people. But as Jesus will say later in John 6 this “bread of life” is his own body which will be given for them (6:48-51).