There is a definite quality about leaven that caused the Holy Spirit to use it in connection with the invasion of false teaching into the body of Divine Truth. Literally leaven is sour dough in a high state of fermentation mixed with new dough to prepare for baking. It was forbidden in the house of the Jews during the seven days of Passover, as a reminder of the haste with which they left Egypt (Deut. 16:3). No offering by fire was to be made unto the Lord with leaven (Lev. 2:11).

In the New Testament the idea of leaven was used to illustrate the effect of teaching, especially false doctrine. Since its fermenting quality indicated the effect upon new dough, the corrupting quality of error upon truth is the comparison. It also indicated corrupt practices as in the case of the fornicator in 1 Corinthians 5:6-7.

In Matthew 16:6-12 Jesus warned the disciples to “Take heed and beware of the leaven of the Pharisees and of the Sadducees.” Although the doctrines of these two religions differed widely, the same admonition was given regarding both. It makes no difference what the nature of the false doctrine is, we must beware of it. The disciples thought Jesus was talking about the fact that they had brought no bread, but he explained: “Then understood they how that he bade them not beware of the leaven of bread, but of the doctrine of the Pharisees and of the Sadducees. ” There are some outstanding comparisons between the working of error and the working of leaven in bread. These are the points indicated in the statements just read from the word of God:

  1. Leaven works silently and secretly.
  2. It spreads by contact.
  3. It affects the whole lump.
  4. It changes every particle with which it comes in contact into its own kind.
  5. It can only be destroyed by purging it out of the lump; no part of it can be permitted to remain or it will begin its work over again.
  6. It takes only a “little” to do the job.

The Lord gave a perfect illustration of the working of false teachers in the body of his disciples.

Paul told the Corinthians what to do about the leaven working among them: “Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us” (1 Cor. 5:7). He warns: “A little leaven leaveneth the whole lump” (Gal. 5:9). We must oppose sin in any form and to every degree in the church or suffer the whole body to be affected and destroyed by error. We had better learn this lesson well if we want to remain the peculiar people of God.

Since Jesus used the term “leaven” to describe the false and hypocritical teaching of the Pharisees and Sadducees, it is important to learn what this meant to the people to whom he spoke. These religious leaders came from the descendants of the twelve sons of Jacob who were delivered from Egyptian bondage and led by Moses to the mount where the law was given to Moses for the people. The law prescribed in detail the worship, priesthood, personal behavior and duties to God and their fellow man. The use of unleavened bread and the rejection of all leaven during the week of Passover was well known by every descendent of those to whom the law was delivered.

The Passover was instituted in Egypt before the children of Israel were delivered from bondage. The blood of the slain lamb without blemish was to be put on the side posts of the door and the upper door post. The first born of all in Egypt would die that night where the blood was not on the door posts. This feast of Passover was to be observed every year to the end of the Jewish dispensation. “And this day shall be unto you for a memorial; and ye shall keep it a feast to the Lord throughout your generations; ye shall keep it a feast by an ordinance for ever” (Exodus 12:14).

One important thing about this feast that was to be observed with strictest care was that no “leavened” bread was to be used during the seven days of the Passover. The law said all leaven was to be put out of the house for the seven days. No one was to eat any leaven. Anyone who did eat leavened bread was cut off from Israel (Exodus 12:15). Even strangers were cut off if they ate any leaven (Exodus 12:19).

For seven days they were to eat unleavened bread. “Unleavened bread shall be eaten seven days; and there shall no leavened bread be seen with thee, neither shall there be leaven seen with thee in all thy quarters” (Exodus 13:7).

The apostle Paul described the church at Corinth as being unleavened, and therefore, they should put away the leaven of immorality: the man among them who was guilty of adultery. This is what the Holy Spirit said: “Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump? Purge out therefore the old leaven, that ye may be a new lump, as ye are unleavened. For even Christ our passover is sacrificed for us: Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth” (1 Cor. 5:6-8).

Jesus used the word “leaven” to refer to the “doctrine” of the Pharisees and Sadducees, and the hypocrisy of the Pharisees (Matt. 16:6-12). The doctrine of the Pharisees produced vain worship because it was a doctrine based upon the “commandments of men.” The doctrines of men are all doctrines that are not of God. The doctrine of God—the Father, Son and Holy Spirit—is one; the
doctrines of men are all that men have developed throughout the ages. They are all alike in that they reject and pervert the doctrine of God.

Paul said no other gospel was to be received because there was no other from Christ. “But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed. As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed” (Gal. 1:8-9).

The apostle John said: “If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed: For he that biddeth him God speed is partaker of his evil deeds” (2 John 10-11). Anyone who gives sanction or encouragement to those who teach any false doctrine, are as guilty as the false teacher. John said so!

The application of the instruction of Jesus regarding the leaven of false doctrines of men must be made today as it was in the time Jesus made the statements. All leaven must be put away, out of the house. No one can partake of that leaven under any circumstances.