What does John 6:13 mean?

Jesus does more than just miraculously feed upwards of 5,000 people (John 6:10) with the contents of a boy's small lunch (John 6:9). He turns that small offering into so much food that the disciples use twelve baskets collecting the leftovers. This was after the disciples all but gave up on feeding such a large throng of people (Mark 6:36; John 6:7–9). The task seemed too large and the resources available seemed too small.

The disciples' problem, essentially, wasn't that there was something wrong with thinking of money, or food, but that they were approaching the situation backwards. Rather than trying to scrape up something worthy of God, then offering it, Jesus taught them to simply bring whatever they had to God—first and foremost—and let Him work from there. When there is a need, our first response needs to be trusting God to provide for it. Our efforts are still meaningful, but God's will controls the outcome, and we're meant to rely on His power. Likewise, what we think of as "too little"—whether it's our skills, our talents, or our resources—can become "more than enough" when we give it entirely to Jesus.

Jesus' miracles are what drew the crowd to Him in the first place (John 6:2). This particular miracle would have reminded the crowd of the Old Testament prophet Elisha, who also miraculously multiplied loaves of barley bread (2 Kings 4:42–44). Jesus' miracle feeds some fifty times as many people, with even less to start with. This, combined with other Old Testament prophecies (Deuteronomy 18:15), is likely what led the audience to declare that Jesus was this long-awaited prophet (John 6:14).