Then he said to them, “Do you still not understand?” Mark 8:21
John Piper did a quick meditation on Mark 8:21. He asks what the Apostles did not understand, concluding, “What didn’t they understand? That Jesus would take care of them. You can’t outgive Jesus. When you spend your life for others, your needs will be met”.
This seems weird to me as this is not what the Scriptures say about the incident. To set the stage, Jesus had just had a run in with the Pharisees. They demanded a sign from Jesus (v11) which Jesus refused to do (v12). Leaving there, they got in a boat And Jesus ordered them, Watch out! Beware of the yeast of the Pharisees and the yeast of Herod! (Mark 8:15). Then the Apostles started discussing the fact that they forgot to bring bread (v16). Jesus asked why they are discussing bread in response to his statement and reminded them of the two incidences where he fed the multitude. Though it does not say this in Mark, Matthew says, Then they understood that he had not told them to be on guard against the yeast in bread, but against the teaching of the Pharisees and Sadducees. (Matthew 16:12) What the Apostles did not understand is that when Jesus warned them concerning the yeast of the Pharisees, he meant their teaching, which also applies to the incident before getting in the boat where they interacted with Jesus trying to disrupt him and his mission.
But why did he mention the feedings? The Apostles were not complaining about being hungry or missing out on anything. They were talking about bread because they thought Jesus had brought it up. Jesus specifically mentioned the remaining food so I think this is part of the lesson.
The first incident was in Israeli territory near the Sea of Galilee. There were 5,000 men there and Jesus starting with five loaves and two fishes fed them all with a remainder of 12 baskets.
The second incident was “near Decapolis” (Mark 7:31) which is Gentile territory. Here 4,000 people were fed. Starting with seven loaves, Jesus fed them with leftovers of seven baskets.
As a child, I remember wondering about the difference in remainders. Starting with five loaves he fed 5,000 with twelve baskets remaining: starting with seven loaves (larger starting point) he fed 4,000 (fewer people) with seven baskets remaining (less extra). Surely, Jesus’ ability to break and multiply the bread was not diminished, nor did he become “more efficient” about feeding people. The answer, then, is that the Gentiles ate more bread. In additional support, the feeding of the 4,000 was in the same area and timed right after the incident where the Syrophoenician woman’s daughter was exorcised from a demon. Leading up to the healing, Jesus said that you “don’t feed the children’s bread to dogs” to which the woman replied, “but the dogs get to eat what the children drop off the table” Once again, gentiles get to eat the bread, which the children reject. Same terminology and the story is placed right between the two feedings.
Given the understanding that Jesus evoked these stories to teach the Apostles that bread is teaching, we see a visual parable that the Jews were not going to accept the Gospel message as quickly as the Gentiles will. In fact, the Apostles could still expect animosity from the Pharisees, just like Jesus received.