Jesus is provoking the religious with His statements; if the statements are true, we must worship Him, if they be false, His blasphemy would carry the punishment of death. Whatever His followers knew, His detractors understood this.
A number of people listen to Jesus preach for a day, and by the end, they are hungry. Jesus finds a boy with five barley loaves and two small fish. With this, five thousand are fed, and the scraps from the loaves (and from no other food) fill up twelve baskets. This event is important enough to be mentioned in all four gospels.
The people there think Jesus to be the prophet mentioned in Deuteronomy 18:15, and want to make Him their king, but Jesus withdraws. Some of the people meet up with Jesus and ask Him about more miracles of bread. Jesus tells them that for God, providing them with food is nothing compared with providing them with what they really need, the bread of life, which Jesus provides for us in the Eucharist.