Did Jesus have the tradition of preserving of leavening agent in mind, while speaking of the Pharisees' Yeast?

Question

We read in Matt 16: 6-12 (NRSVCE):

Jesus said to them, “Watch out, and beware of the yeast of the Pharisees and Sadducees.” They said to one another, “It is because we have brought no bread.” And becoming aware of it, Jesus said, “You of little faith, why are you talking about having no bread? ........... Then they understood that he had not told them to beware of the yeast of bread, but of the teaching of the Pharisees and Sadducees.

In the days of Jesus when dry yeast was not in vogue, people preserved a small portion of leavened dough, for use on a subsequent occasion. This is clear from the Parable of the Yeast in Mtt 13:33:

He told them another parable: “The kingdom of heaven is like yeast that a woman took and mixed in with three measures of flour until all of it was leavened.”

If the woman needed one measure of yeast for three measures of flour, it would not have been in the form of dry yeast we have these days, but of leavened dough set apart from previous baking.

Now, leavening was considered good because it gave taste and softness to the bread and increased its shelf life. There were two options available to the breadmaker: he/she could refresh the leaven day after day by preserving the leavened dough of the most recent baking. Alternatively, one could preserve a large portion of leavened dough from the first day of baking say, Sunday and use small portions of it for leavening the flour through the full week. That would make the leaven too sour for want of renovation, but it would still act as a leavening agent.

The Pharisees and Sadducees clearly showed scrupulous adherence to the Old Law which Jesus wanted to supplement with the New Law. Jesus' way of referring to the yeast, was meant to expose the confrontation. In the literal sense, he was referring to the fermented dough that had been kept too long, but it was still being used as a leavening agent. My question therefore is: Did Jesus have in mind the tradition of preserving of leavening agent, while speaking of the Pharisees' Yeast? Inputs from any denomination are welcome.

Answer 1

In Luke 12 Jesus tells us exactly what the leaven of the Pharisees is: hypocrisy.

In the mean time, when there were gathered together an innumerable multitude of people, insomuch that they trode one upon another, he began to say unto his disciples first of all, Beware ye of the leaven of the Pharisees, which is hypocrisy. - Luke 12:1

It is not so much the Old Covenant vs. the New Covenant which is in view in this teaching as it is the hypocritical mishandling of the Old Covenant law by the religious leaders of the day.

In Matthew 23 Jesus makes 7 distinct pronouncements of Pharisaic hypocrisy all the while upholding the Law. He tells His disciples to do what they say because they sit in Moses seat of authority but not to do what they do because they are wrongly motivated:

Then spake Jesus to the multitude, and to his disciples, Saying, The scribes and the Pharisees sit in Moses' seat: All therefore whatsoever they bid you observe, that observe and do; but do not ye after their works: for they say, and do not. For they bind heavy burdens and grievous to be borne, and lay them on men's shoulders; but they themselves will not move them with one of their fingers. But all their works they do for to be seen of men: they make broad their phylacteries, and enlarge the borders of their garments, And love the uppermost rooms at feasts, and the chief seats in the synagogues, And greetings in the markets, and to be called of men, Rabbi, Rabbi. - Matthew 23:1-7

So, in Matthew 16 Jesus uses the word διδαχή which is generally rendered as doctrine but this word covers the action of the teacher as well as the content of the teaching. Therefore, Jesus is telling the disciples to beware of the hypocritical action of the Pharisees and not the content of the teaching.

This is the leaven of the Pharisees ... beware of hypocrisy, it spreads!

Answer 2

The straightforward meaning of using the illustration of yeast to apply to Pharisaical teaching is in yeast's property of spreading throughout the dough it is mixed into, to make the dough rise.

Yeast enlarges the initial 'ball' of dough. It makes it 'rise'. At least double more dough results. When we hear another statement of Jesus regarding those teachers, we see how he refers to the spreading of their teaching:

"Woe unto you scribes and Pharisees, hypocrites! For ye compass sea and land to make one proselyte, and when he is made, ye make him twofold more the child of hell than yourselves." Matthew 23:15 K.J.V.

The last thing Jesus wanted was the preserving of the traditions of the Pharisees' that made others candidates for hell!