Leaven (Noun and Verb) - Vine's Expository Dictionary of New Testament Words
Leaven (Noun and Verb)[ A-1,Noun,G2219, zume ]
leaven, sour dough, in a high state of fermentation," was used in general in making bread. It required time to fulfill the process. Hence, when food was required at short notice, unleavened cakes were used, e.g., Genesis 18:6; Genesis 19:3; Exodus 12:8. The Israelites were forbidden to use "leaven" for seven days at the time of Passover, that they might be reminded that the Lord brought them out of Egypt "in haste," Deuteronomy 16:3, with Exodus 12:11; the unleavened bread, insipid in taste, reminding them, too, of their afflictions, and of the need of self-judgment, is called "the bread of affliction." "Leaven" was forbidden in all offerings to the Lord by fire, Leviticus 2:11; Leviticus 6:17. Being bred of corruption and spreading through the mass of that in which it is mixed, and therefore symbolizing the pervasive character of evil, "leaven" was utterly inconsistent in offerings which typified the propitiatory sacrifice of Christ.
In the OT "leaven" is not used in a metaphorically sense. In the NT it is used
(1) of corrupt doctrine, Matthew 13:33; Luke 13:21, of error as mixed with the truth (there is no valid reason for regarding the symbol here differently from its application elsewhere in the NT); Matthew 16:6, Matthew 16:11; Mark 8:15 (1st part); Luke 12:1; that the kingdom of heaven is likened to "leaven," does not mean that the kingdom is "leaven." The same statement, as made in other parables, shows that it is the whole parable which constitutes the similitude of the kingdom; the history of Christendom confirms the fact that the pure meal of the doctrine of Christ has been adulterated with error;
(2) of corrupt practices, Mark 8:15 (2nd part), the reference to the Herodians being especially applied to their irreligion; 1 Corinthians 5:7-8;
(b) literally, in Matthew 16:12, and in the general statements in 1 Corinthians 5:6; Galatians 5:9, where the implied applications are to corrupt practice and corrupt doctrine respectively.
[ B-1,Verb,G2220, zumoo ]
signifies "to leaven, to act as leaven," Passive Voice in Matthew 13:33; Luke 13:21; Active Voice in 1 Corinthians 5:6; Galatians 5:9.