The Blindness of the Disciples Rebuked (Mark 8:14-21 *, Luke 11:53 f., Luke 12:1). Note how Mt avoids the idea that Jesus had forgotten the bread. The Sadducees are mentioned again in 6. The detached saying about leaven in Mark 8:15 probably refers to plots of the Pharisees and Herod, but Mt. (Matthew 12) interprets leaven as teaching, and so has to substitute Sadducees for Herod, and carries the substitution back to Matthew 16:1. He makes Jesus read the disciples-' thoughts (Matthew 16:8) instead of simply overhearing their conversation (Mk.). Then, after giving Mk.'s statement that the disciples need never worry about a shortage of food, he adds words of Jesus that the point at issue is not food at all, but erroneous teaching. Matthew 16:11 f. is an attempt to give Mark 8:15 a context and explanation.
Matthew 16:5-12
5 And when his disciples were come to the other side, they had forgotten to take bread.
6 Then Jesus said unto them,Take heed and beware of the leaven of the Pharisees and of the Sadducees.
7 And they reasoned among themselves, saying, It is because we have taken no bread.
8 Which when Jesus perceived, he said unto them,O ye of little faith, why reason ye among yourselves, because ye have brought no bread?
9 Do ye not yet understand, neither remember the five loaves of the five thousand, and how many baskets ye took up?
10 Neither the seven loaves of the four thousand, and how many baskets ye took up?
11 How is it that ye do not understand that I spake it not to you concerning bread, that ye should beware of the leaven of the Pharisees and of the Sadducees?
12 Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees.