The Demand for a Sign and the Leaven of Unbelief

Pharisees ask Jesus for a sign from heaven to test him. Jesus sighs deeply and refuses the demand. In the boat he warns the disciples about the leaven of the Pharisees and of Herod, but they think he is criticizing their lack of bread. Jesus responds with a barrage of questions about eyes, ears, memory, and the two feedings.

Where this fits in the story: Mark distinguishes seeing a miracle from understanding what it reveals. The disciples can count leftover baskets yet still miss the identity and sufficiency of the one who provided them.