In today's Gospel we see the blindness of Jesus' own disciples, pointing, of course, to our own blindness in not recognising the clear presence and loving action of God in our own lives. As they cross the lake in the boat they realise they took no bread with them. Jesus is talking to them and warning them to avoid the yeast of the Pharisees and Herod. For the Jews yeast was a corrupting agent because it caused fermentation. The yeast of the Pharisees was their narrow-minded legalism and that of Herod his selfish pleasure-seeking. But the disciples can only think of their shortage of food. Jesus had just recently fed 5,000 people and then 4,000 and on each occasion there was an abundance of food left over. Why should they worry now about a few loaves of bread among a small number of people? But they latch on to the word "yeast" and link it with their present obsession - not enough bread. Their lunch is the only thing on their minds and Jesus is well aware of that. They cannot see, they cannot hear, they fail to understand the meaning of what is happening before their very eyes. But they are learning gradually, as we shall see. Of course, Mark is firing his shots not at the disciples but at you and me. How much faith have we got in God's care for us? Can we hear, can we see? Are we also without understanding?