After Jesus had fed 4000 people with only seven loaves of bread and few small fish, He worked His way around the coast of the Sea of Galilee where He was confronted by some Pharisees, and possibly some Sadducees, asking Him for a sign from Heaven. Jesus rebuked them for their request, and for not already understanding the signs of the times. Jesus and His disciples soon left there for another spot on the coast of the Sea of Galilee.
Beware of Yeasty Priests
This is another episode where it makes sense to start with Mark, the earliest of the Gospels. In Mark 8:14-21, Jesus tells His disciples to beware of the "yeast of the Pharisees and that of Herod." His disciples, portrayed as being dumber than dirt, discuss among themselves that Jesus must be saying this because they forgotten to bring enough bread for their journey.
Why say that they appear dumber than dirt? Well, the bread that the Pharisees would have would be deemed Holy, and not available to distribute to the common people. As for Herod, it is unfathomable that they would even think of getting bread directly from their ruler. Clearly Jesus means something other than literal bread here, but what? It seems that the disciples were too distracted by the potential food problem to understand the absurdity of their own conclusion.
Jesus, sensing that the disciples did not understand what He had just said, does what any great teacher would do. He helped them understand... No. Wait, that is not right.
Instead, Jesus focused on the bread-shortage issue. He asks His disciples to remember about the miraculous feeding of the 5000 and the 4000 people, and then asks them if they still do not understand. These miraculous feedings have absolutely nothing to do with Jesus' earlier statement about the yeast of the Pharisees and Herod. Instead, Jesus seemed to be reminding His disciples that they should not worry, because God will provide for them, just like He had said earlier in the Sermon on the Mount.
And that is it. Mark's account ends with no explanation about this mysterious yeast, which is obviously not really yeast. Fortunately, Matthew fixed that issue when he copied the story in Matthew 16:5-12. Matthew's version is mostly the same as Mark's, with a couple of notable exceptions.
In Matthew 16:6, Jesus tells His disciples to "guard against the yeast of the Pharisees and Sadducees." So Matthew changed Herod to be the Sadducees. Christian commentators generally waive this discrepancy because Herod had sided with the sect of the Sadducees over the Pharisees, and so, in a manner of speaking, he represented the Sadducees. That is certainly possible, but then Mark's use of a general term (Pharisees) to refer to a group and then a specific term (Herod) to instead represent a different group in the same sentence and context is linguistically awkward.
The other notable difference is in Matthew 16:12, where we finally discover what this mysterious yeast is:
Then [the disciples] understood that [Jesus] was not telling them to guard against the yeast used in bread, but against the teaching of the Pharisees and Sadducees. NIVNote Jesus had not actually told His disciples what He had meant by "yeast." Matthew's account followed the same pattern as Mark's, switching to a questioning of whether or not they understood the fact that God would provide food for them if they needed it. No, the disciples had figured out this meaning on their own.
Jesus was said to be a teacher, and good teachers must often try to nudge their own students (disciples) into figuring things out for themselves to promote true understanding. Students must be able to conceptually add two plus two, instead of just memorizing that the answer is four. So we should not be too hasty to judge Jesus for not explaining everything ad infinitum, but, at the same time, when you are dealing with less concrete concepts than basic mathematics, when you are dabbling in the language of metaphor, it is pretty important that you verify your students come up with correct understanding; that which we find in Luke.
Luke 12:1 does not give the episode which we found in Matthew and Mark, but it does have the same concept at heart, as you can see in an excerpt from that verse:
... Jesus began to speak first to His disciples, saying: "Be on your guard against the yeast of the Pharisees, which is hypocrisy." NIVLuke's version shows Jesus to be a better teacher, where Jesus gives the metaphor and explains the symbolic meaning enough to be easily understood. Hypocrisy is the "yeast," and if only a little yeast gets into a pure flour dough, the yeast will spread throughout it. So stop hypocrisy as soon as you find it, or else it can spread. It is a good metaphor and a good teaching.
There is just one problem; both Matthew and Luke cannot be right. OK, well, technically they could both be right, but it seems extremely unlikely. Matthew claims that the teaching is the yeast. Luke claims that the hypocrisy is the yeast. In the most common way in which "hypocrisy" is used, it is not a condemnation of the rules, ideals, or teachings, but rather condemnation of people who espouse rules, ideals, or teachings yet do not abide by them. In fact, for Jesus to claim that hypocrisy is the yeast, it could be claimed that it is a tacit approval of what the Pharisees were teaching.
Did you notice that Luke dropped the reference to the Sadducees? One of the primary divisions between the Pharisees and the Sadducees is that the Pharisees had a concept of the afterlife, but Sadducees rejected that notion. In that way, the teaching of the Pharisees was in alignment with the message of Christianity.
But wait! (Objectors scream.) Jesus had condemned the teaching of the Pharisees earlier in the Gospels as being the teachings of man!
Yes, well, Luke was a bit of an editor when it came to creating his Gospel. As was discussed in an earlier study, Matthew 15:1-20 and Mark 7:1-23 are the sections accusing the Pharisees teaching man-made law, and they are the only parts of the Gospels to do so. Luke 11:37-41 took that same message and rewrote it as an attack on the hypocrisy of the Pharisees. The earlier study contains a strong suggestion about why Luke may have felt the change was necessary; essentially to prevent Jesus from, Himself, appearing to be a hypocrite.
So we find Matthew to be consistent with his view, and Luke to be consistent with his own view as well, but, together, they represent contradictory aspects, and thus must prompt doubt of accuracy between the Gospels.