Jesus gives a warning to the disciples to not let their spiritual vision be dimmed by the leaven of the Pharisees and Sadducees.
They must stay alert to that leaven and keep their distance from it. Since the Pharisees and Sadducees usually were opposed to each other, the fact that Jesus treats them as a unit recalls their recent joint effort to test him. The antidote to this leaven is to look with faith at all Jesus does and teaches. Seeing him rightly is the best cure for blindness. The metaphor of leaven suggests something that spreads through the whole: the people being permeated by the Pharisees and Sadducees’ aversion to Jesus and their undermining of his works and words. Leaven or yeast is an apt image in Jesus’ day, where leaven was seen as unclean and had to be removed from every household before Passover, the feast of deliverance. Jesus’ words here evoke that association. As he works liberation through his miracles and signs, he himself is the sign of unleavened bread, so the people must remove the old leaven: the corrupting influence of the Pharisees and Sadducees. The context shows that the leaven is their unbelieving view of Jesus—not a wrong view of the law—since what the two groups now have in common is their joint rejection of the Saviour (Matthew 16:1–4). The leaven of the Pharisees and Sadducees thus means both their mindset and the teaching that flows from it (see Matthew 16:12), with its infectious influence upon the people that leads them to reject Jesus’ instruction. The disciples must not be infected by this influence, but must separate themselves from it.
Jesus combines this command with a warning. The disciples’ spiritual perception can easily be clouded by the leaven of the Pharisees and Sadducees.
They must therefore remain alert to it and keep their distance from it.
Since the Pharisees and Sadducees normally stood at opposite ends of the Jewish spectrum and were rarely mentioned together, the fact that Jesus now treats them as a unit clearly recalls their recent joint attempt to test him. This double reference therefore points back to the immediately preceding encounter. The antidote to this leaven is that the disciples must look with open, discerning eyes at Jesus—at everything he does and teaches. In this case, seeing rightly is the best cure for blindness.
The metaphor of leaven suggests a pervasive influence—something that spreads through the whole. The people were being subtly permeated by the leaven of the Pharisees and Sadducees. Their aversion to Jesus and their insinuating undermining of his works and words were gradually seeping into the nation.
Leaven or yeast is not inherently negative of course, but Jesus here employs an apt image in a historical context where leaven was considered unclean and had to be removed from every household before Passover. As the feast of deliverance approached, God’s people cleansed their homes of all yeast. Jesus’ words here are intended to evoke that association.
Now, as he comes to his people and works among them in a liberating way through his miracles and signs, he himself is the sign of unleavened bread. Therefore, the people must remove the old leaven—that is, the corrupting influence of the Pharisees and Sadducees.
The context makes it clear that the leaven refers to their unbelieving attitude toward Jesus. It would be a mistake to interpret this more generally, as if it referred merely to a wrong relationship with the law. After all, Jesus is here referring to what the two groups have in common—their joint rejection of the Saviour (Matthew 16:1–4).1
The leaven of the Pharisees and Sadducees therefore refers to their mode of thinking, as well as the teaching that proceeds from it (see Matthew 16:12), which exerted an infectious influence upon the people and led them to reject Jesus’ instruction. The disciples were not to be deceived or drawn in by this influence, but to separate themselves from it.2
5 Les disciples, en passant sur l'autre bord, avaient oublié de prendre des pains.