Mark 8:17 (AMPC): "And being aware [of it], Jesus said to them, Why are you reasoning and saying it is because you have no bread? Do you not yet discern or understand? Are your hearts in [a settled state of] hardness?"

Leading up to this moment, Jesus had performed the second miracle of feeding thousands with very little. This time they only had seven loaves of bread. After everyone had eaten their fill, there were seven baskets left over. Then Jesus and His disciples sailed away from that place and were immediately confronted by Pharisees who had hardened hearts of unbelief, and demanded a sign to prove Jesus was who He said He was. Annoyed, Jesus left them and sailed away. In the boat, while Jesus was warning the disciples to avoid having hardened hearts of unbelief like the Pharisees, saying unbelief prevents them from having eyes of faith; the men realized they hadn't brought enough bread for the trip. They completely misunderstood Jesus' stern teaching and thought He was rebuking them for not bringing enough bread. Can you imagine His frustration? He reminded them of the two recent occasions where He proved the amount of bread is never an issue with Him. It's hearts that only focus on the natural limitations of challenges and are hardened with unbelief that are the issue. When a challenge arises, even when we know God and see His faithfulness in all things, we must be careful to not allow unbelief to harden our hearts and blind us from seeing through eyes of faith. He has proven Himself faithful - so keep your heart full of trust, seeing Him, not the problem.