LEAVEN lĕv’ ĕn (1) שְׂאֹר, H8419, LXX ζύμη, G2434, Vul. fermentum. Root meaning unknown. Occurs five times (Exod 12:15, 19; 13:7; Lev 2:11; Deut 16:4). (2) חָמֵצ֩, H2809, LXX ζύμη, G2434, Vul. fermentum. From a root “to be sour.”

1. Literal. Bread was made to rise by putting a piece of sour dough from a previous batch of dough in the flour, which dough in turn brought on fermentation of the whole. Leavened bread was a regular part of the diet of ancient Israel (Hos 7:4). Bread made in haste without rising is called “unleavened bread” (Maṩṩot, LXX azúmē, Vul. Azyma; Gen 19:3; Exod 12:15; Judg 6:19; 1 Sam 28:24; etc.). The haste to depart from Egypt left no time for bread to rise, therefore the people carried with them dough and kneading troughs (Exod 12:34, 39).

In memorial of the Exodus and its hurried flight (12:11, 39; Deut 16:3) Israel was commanded to cast out annually leaven from the house on the fourteenth day of the first month (Abib) and to eat unleavened bread (“the bread of affliction” [Deut 16:3]) for seven days—the fourteenth to the twenty-first day—as the feast of unleavened bread (Exod 12:14-20; 13:4-7; 23:15; 34:18; Num 28:17; 2 Chron 35:17; cf. Matt 26:17; Mark 14:1, 12; Luke 22:1; Acts 12:3; 20:6 [see Feasts]). The penalty for the native or sojourner who ate that which was leavened in this period was to be cut off from the congregation (Exod 12:15-30; 13:7).

This prohibition of leaven was interpreted to prohibit that which is fermented from grain rather than that from the grape (M. Passover 3:1). There is no mention in the Mishna of wine lees as leaven. The prohibition of leaven did not prohibit the drinking of wine at passover. The rabbis ruled that the poorest man in Israel was entitled to four cups even if it had to be supplied by charity (M. Passover 10:1).

The use of leaven and honey are prohibited in cereal offerings and blood offerings made by fire (Lev 2:11; 6:17; 7:12; 8:2, 26; 10:12; Exod 23:18; 29:2, 23; 34:25; cf. Amos 4:5); but the use of leaven is permitted in peace offerings, which offerings man consumed (Lev 7:13), and permitted in the wave loaves of the firstfruit offering (23:17). Leviticus is not explicit that the showbread should be unleavened, but we are informed by Josephus (Antiq. III. vi. 6; X. 7) that it was.

2. Figurative. The significant thing about leaven is its power, which power may become a symbol of either good or evil. Jesus, in the parable of the leaven (Matt 13:33; Luke 13:21) used the working of leaven to teach the pervasiveness of the kingdom which eventually transforms the world. The small bit of leaven—the Word—has power to accomplish this great result. The final point of the comparison is the whole lump permeated by the leaven. This parable is one of a pair with the parable of the grain of mustard seed. Philo (Spec. Leg. II. 184f.) seems also to use leaven as a symbol of something good. Scofield et al., on the other hand, insisting that leaven in Scripture is always a symbol of evil, attempts to make the parable a picture of the true teaching being mingled with corrupt and corrupting false doctrine resulting in the final apostasy of the professing church. One’s approach to this issue is ordinarily determined by a prior decision on the question of whether the NT outlook for the kingdom is optimistic or pessimistic.

Leaven also is a symbol of undesirable teaching used by Jesus in warning against the “leaven of the Pharisees and Sadducees” (Matt 16:6, 11, 12). The parallel in Luke 12:1 reads: “the leaven of the Pharisees which is hypocrisy.” This interpretation turns aside any possible misunderstanding that Jesus is warning against the bread of the Pharisees as the rabbis warned against the “leaven or meat” of the Samaritans which is interpreted by some rabbis to be a warning against mixed marriages (SBK I. 541f.). Mark 8:15 has a warning against the “leaven of the Pharisees and the leaven of Herod [or some MSS ‘Herodians’].” Leaven as a symbol of the undesirable is paralleled in the rabbis who called the evil desire (yeṩer hara’) the leaven that is in the dough” (T. B. Ber. 17a; Gen. R. 34:12).

Paul uses leaven as a symbol of the pervasiveness of evil (1 Cor 5:6) and makes an allegory on the casting out of leaven at Passover. Here malice and evil are the leaven which need to be replaced by sincerity and truth that the festival may be celebrated (1 Cor 5:7, 8). Paul also uses leaven as a symbol of evil which has power to influence the whole as he cites the proverb “a little leaven leavens the lump” (1 Cor 5:6; Gal 5:9).

Bibliography SBK (1926), I, 728; H. Windisch, “Zume,” TWNT (1935); II, 904-908; J. Jeremias, The Parables of Jesus (1955), 89, 90.