4 Aug 2021

Leaven/Yeast: Assumptions and Bad Bible Reading

Author: Bobby Valentine | Filed under: Exegesis, Hebrew Bible, Jesus, Jewish Backgrounds
Oat flakes, seeds and bran in spoons

Assumptions, Bad Bible Reading, and Leaven/Yeast

A Quote to Begin with: “Leaven in the Bible, without exception, is used as a symbol of corruption by unclean or sinful things … Throughout the Hebrew scriptures, leaven is a symbol of the unholy” (David Buttrick, Speaking Parables: A Homiletic Guide, p.147).

Is leaven (or yeast) a symbol of corruption, uncleanness, or sin in Scripture? Many have made such claims. Leaven is this microscopic (even invisible!) substance that invades from without (like secret sin). Thus Jesus famously said we are to “avoid the leaven/yeast of the Pharisees” (Mt 16.6). And at the Passover, Jews were instructed to clean their house so that no leaven could be found (interesting instructions if leaven/yeast is invisible!). Leaven is bad. I’ve heard/read these statements many times over the years.

But these statements, that can even be documented in some scholarly materials, simply conflates the historical gap between the biblical text and our own lives. We know what “yeast” is in our modern world, microbes right. Essentially germs. However, no one in Israel/Palestine in either Moses’s day nor Jesus’s day knew about “yeast/leaven” in such a scientific fashion. That was not known until Louis Pasteur.

Not only is the historical/cultural context simply ignored and we assume that yeast means what it does in today’s kitchen, it ignores the Hebrew Bible and second temple Judaism. Leaven/yeast must be those little organisms that we know today.

Let me put the cards on the table. In Scripture “leaven” (NRSV) or “yeast” (NIV) is a neutral metaphor. There is nothing inherently negative about the symbolism of leaven/yeast anywhere in Scripture. The use of leaven, as a symbol, depends on the context. By itself, leaven is positive. Leaven can have a negative meaning in a given context.

First, leaven is not invisible in the ancient world. All around the Mediterranean, including Palestine, what we call “leaven/yeast” is what a modern chef might call a “sourdough starter” and not stuff in little red packets. And it was never regarded negatively in Jewish culture.

Second, what about the Passover? Israel was indeed commanded to remove all the yeast from the house. But here we simply do not read the Scriptures very closely. The yeast/leaven is not removed, according to Exodus, because it is unclean. The unleaven bread symbolizes the haste in which Israel left. Israel was in such a hurry to flee Egypt there was not even time to make bread (Exodus 13). In the Passover it is the bitter herbs that remind Israel of the misery and suffering of slavery in Egypt, not leaven. The bitter herbs might be considered a negative image.

There are sacrifices in which leaven is excluded as well but the rational is never given.

On the other side of the coin, leaven/yeast is commanded to be used in thanksgiving /fellowship offerings to Yahweh. The leavened bread is offered to the Lord and eaten (Lev 7.13ff).

With your thanksgiving of well-being you shall bring your offering with cakes of leavened bread. From this you shall offer one cake from each offering, as a gift to the LORD …”

This is one of the most common offerings in the Hebrew Bible.

The regulations for the the Feast of First Fruits/Weeks/Pentecost are very different than Passover on the matter of leaven/yeast. No requirement for avoiding yeast is to be found anywhere. Such would have been impractical at best. Grapes and barely harvest are pretty difficult to not have yeast. Grapes naturally have yeast that live on the skin (and if we think leaven is microbes, you would think God knew about those invisible things on the grape) and begin to make wine the instant the skin is broken and barley is used in the beverage known as beer. There was a reason the disciples could have been accused of being slightly intoxicated on Pentecost, because “leaven/yeast” is not excluded from Pentecost. But without any of that, leaven/yeast is simply commanded.

You shall bring your from your home two loaves of bread as an elevation offering, each made with two-tenths of an ephah; they shall be of choice flour, baked with yeast/leaven, as first fruits to the LORD …” (Lev 23.17)

This leavened bread is offered along with the leavened drink offering (wine. Israelites did not consider wine to be leavened, again because they associate leaven with the bread), you invite the priest and the poor and then eat and drink in the presence of the Lord. I add that the shewbread used in the daily offerings in the Temple were made out of leavened bread. Clearly not unclean. The “daily bread” Jesus teaches us to pray for is leavened bread.

The Lord Jesus compares the kingdom of God to leaven, surely he is not casting negativity on the kingdom.

He told them another parable: ‘The kingdom of heaven is like yeast/leaven that a woman took and mixed with three measures of flour until it was all leavened” (Mt 13.33)”

And again he said, ‘To what should I compare the kingdom of God? It is like yeast/leaven that a woman took and mixed in with three measures of flour until all of it was leavened.” (Lk 13.20-21).

Yeast/leaven is another one of the wonderful examples of what simply assuming can do. I once assumed that “milk and honey” referred to white stuff from a cow and sweet stuff from bees. I was wrong! (See The Bible and Assumptions: The Case of Milk and Honey).

In the ancient world leaven/yeast was most frequently a symbol of life not uncleanness and sin. In the ancient church, Greek speaking church, leaven/yeast is used in powerful ways as symbols of the incarnation, of the resurrection and of life itself. Leaven is the “life” of the bread.

Jesus’s warning to be on guard against the “leaven” of the Pharisees was a warning regarding a certain kind of leaven. Not that leaven itself is corrupt or unholy. We, however, are supposed to be a leaven in the world.

When Jesus tells us to avoid the leaven of the Pharisees he means a particular kind of living. Paul also has particular kind of leaven in mind in 1 Cor 5.8, the leaven of malice and envy. N. T. Wright once noted in Jesus and the Victory of God, “texts matter, but contexts matter more.”

This is apropos for reflecting on leaven. Leaven is commanded. Yeast is used in worship. Without yeast, wine is impossible The kingdom of God is the yeast of God. None of which is bad.

I will give Ignatius of Antioch the final word. Ignatius was a bishop in the Antioch church that supported Paul. He was born in the first century and martyred no later than AD 117. His seven letters were deeply treasured by the early church and sometimes even regarded as inspired. In his Letter to the Magnesians he shows us how leaven was used both good and bad.

Put aside then the evil leaven, which has grown old and sour, and turn to the new leaven, which is Jesus Christ. Be salted in him, that none among you may be corrupted, since by your savor you shall be tested.” (10.2-3).

We often import filters to the biblical text, especially the New Testament, because we have uninformed or prejudicially informed views of first the Hebrew Bible and secondly of the Judaism of Jesus’s day. Sometimes we can completely miss the meaning because of this.

For more on leaven in the Bible see Amy Jill Levine, Short Stories by Jesus: The Enigmatic Parables of a Controversial Rabbi. Levine is a brilliant Jewish NT scholar. She chastises a NT scholarship for a deeply selective reading of the Hebrew Bible and simply never getting to know the culture in which Jesus lived and taught. Add Levine to your “who I read” list.

Of Related Interest: See How Leavened Bread was used in the early church for the Lord’s Supper.

The Bread on the Table: An Ancient Controversy that Changed the Lord’s Supper

2 Responses to “Leaven/Yeast: Assumptions and Bad Bible Reading”

  1. Gary Huff Says:

    Great article! I worshipped once at an Orthodox church but did not partake of the Eucharist elements during the Divine Liturgy. I spoke with a priest who explained why the Orthodox use leaven bread and wine. After the liturgy, the priest offered non Orthodox visitors a sample of the unconsecrated bread. Sure better than the cardboard tasting wafers we are using now in the “rip and taste” disposable communion containers.

  2. Dwight Says:

    Nice. One reason leaven is conflate with sin is that one of the Temperance Movements argument was that wine was leavened grape juice, thus sinful, but this reaching to find a reason and wrong in what was really going on.


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