What does Matthew 14:21 mean?

The total number of people who ate the food Jesus created from five loaves and two fish could easily have been 15–20,000. This verse reveals that five thousand "men" were present, specifically not counting the women and children. How did they come up with such a precise number of men since crowds are notoriously difficult to count? Mark's telling of the story shows that Jesus had the men sit in groups by hundreds and fifties (Mark 6:40). Jesus wanted the disciples to be able to come up with an accurate number of those fed to be able to provide a reliable report about the miracle.

One other reason this miracle is so impressive: God fed His people food. During a time when poverty was commonplace, Jesus showed that He could create food to provide for His people. That's a thing that God does. Jesus' ability to do this was likely to make the people even more eager to crown Him as Messiah and King. In fact, John's telling of this event ends with Jesus "perceiving then that they were about to come and take him by force to make him king" (John 6:15). Jesus and His disciples quickly left the area.