In Luke 13:20-21 Jesus says the Kingdom of God is like leaven, which a woman took and hid in three measures of meal, until the whole was leavened. Like the mustard seed, many Biblical scholars believe the leaven permeating the whole three measures of flour represents the Gospel going out to the world, until the whole world is brought under the influence of Christ. The problem with this interpretation is that even after 2000 years the whole world has not been brought under the influence of Christ, and even those areas which have heard the Gospel have been corrupted, some even doing violence in the name of Christ.
Notice that, according to Leviticus 14:10 and Numbers 15:9, only oil was to be mixed with the meal offering. In Scripture oil represents light or anointing (Exodus 25:6). Nevertheless, the woman in Jesus’ parable hides leaven in the three measures of meal (Luke 13:19). In the parable she is depicted as acting secretly, hiding the leaven in the meal. The word ,hide (krupto – G2928), is used of the city that cannot be hid (Matthew 5:14); of the hidden treasure (Matthew 13:44); of the hidden talent (Matthew 25:25) and the hidden money (Luke 19:42); of Jesus’ words being hidden from the disciples (Luke 18:34), and of Jesus hiding himself (John 8:59) and 10 other places, usually used in a sense that something occurs that should not be done.
The first time the phrase: “three measures of meal” is mentioned in the Bible is at Genesis 18:6, where Abraham prepared a meal for the Lord and two angels. We are told in the Law that an omer is one tenth of an ephah (Exodus 16:36), and an omer seems to be the measure for one man’s portion (Exodus 16:16). Therefore, Abraham’s three measures of meal was probably three omers (Genesis 18:6).
A single omer, or a tenth deal (part) of and ephah (Exodus 16:36), seems to be what constitutes the smallest of meal offerings in the Law (Numbers 15:4). The usual meal offering, however, was offered with a large amount of meat, and the amount was “three measures of flour” (Leviticus 14:10; Numbers 15:9; 28:12, 20, 28; 29:3, 9, 14). Since Abraham slaughtered a young calf, the three measures of meal represented one meal offering for the Lord and the two angels with him. In 1Samuel 1:24 we find that when Samuel was weaned, his mother Hannah brought him to Jerusalem with three bulls and an ephah of flower. If the ehpah is divided into three parts we would have three meal offerings (cf. Numbers 15:9; 28:12, 20, 28 and 29:3, 9, 14), which were probably used to celebrate her presenting her son, Samuel, to the Lord, who then stayed in the Temple and served there as a priest for the rest of his life.
In Scripture leaven is always used as a type of sin or evil when using it to depict spiritual activity (1Corinthians 5:6-8; Galatians 5:9). It is also used as a metaphor for hypocrisy (Matthew 16:6-12; Mark 8:15; Luke 12:1). As a spiritual metaphor, it was not something desirable. No meal offering was to be offered with leaven (Leviticus 2:11), and since Lot’s meal offering for the two angels was unleavened cakes (Genesis 19:3), we can logically assume Abraham’s three measures of flour was unleavened as well. In the New Testament Paul describes the Church of God as an unleavened lump (1Corinthians 5:7), and, although we are many, we are one bread (1Corinthians 10:17). In this context, what the woman does in Luke 13:21 is unlawful. Jesus’ Jewish audience could not have understood the spiritual meaning of the leaven in the same way many of our modern Biblical scholars understand it.
It seems to me that Jesus is saying that the Kingdom of God, as understood by the people and the Jewish leadership, began as a pure unleavened offering, but corruption was brought by a third party. Leaven had been introduced by the woman, i.e. the Jewish leadership, so that the lump in Jesus’ day was rejecting and would continue to reject the very Messiah who had appeared to rule that Kingdom.