What does leaven symbolize in the Bible?

One online definition of the noun ‘leaven’ is in two parts: 1) ‘a substance, typically yeast, that is used in dough to make it rise’, 2) ‘a pervasive influence that modifies something or transforms it for the better’.[1] We can hardly fault the first of these, but the second is way off the mark in spiritual terms even though many Christians would agree with it because they see leaven as a symbol of the gospel. But wherever we find leaven in Scripture it has a negative connotation: a pervasive influence that modifies or transforms things for the worse. Starting in the New Testament, the Lord Jesus Himself warned His disciples, ‘See and beware of the leaven of the Pharisees and Sadducees’ (Matt. 16:6). They did not understand at first, but later ‘they comprehended that he did not speak of being beware of the leaven of bread, but of the doctrine of the Pharisees and Sadducees’ (v. 12). We could refer to other occasions when He characterised as leaven the words and ways of those religionists — proud and rationalist respectively — and others such as the Herodians (Mark 8:15; Luke 12:1). If we turn to Paul’s letters to the Corinthians and the Galatians, we read: ‘a little leaven leavens the whole lump’ (1 Cor. 5:6; Gal. 5:9). This is in regard to immorality and evil doctrine respectively, and makes their corrupting influence on Christians very clear. In the first case, the apostle goes on to write: ‘let us celebrate the feast, not with old leaven, nor with leaven of malice and wickedness, but with unleavened bread of sincerity and truth’ (1 Cor. 5:8). This is an allusion to the feast of unleavened bread after the passover: ‘Seven days shall ye eat unleavened bread: on the very first day ye shall put away leaven out of your houses; for whoever eateth leavened bread from the first day until the seventh day — that soul shall be cut off from Israel’ (Ex. 12:15). As for the meal offering, the law said: ‘No oblation which ye shall present to Jehovah shall be made with leaven’ (Lev. 2:11). Many more scriptures could be produced to prove the point but these should suffice. Leaven in its penetrating and elevating effect in dough is symbolic of sin’s activity in our lives individually and as families, but also as God’s people.

(1) In the first place, Paul reminds them of what is common knowledge, even apart from the scriptures: “Know ye not that a little leaven leavens the whole lump?” The nature of leaven is such that when a small particle of it is added to a mass of pure dough, its special character is invariably imparted to the whole lump. This diffusive action of leaven is automatic, and requires no human aid. Silently and imperceptibly, the subtle influence is exercised until the secret process of pervasion and amalgamation is completed, and the final result is visible. Hence the baker, after kneading his dough, waits until it is leavened before making up his oven fire for the baking (Hosea 7:4, R.V. ). There is no need that he should assist the leaven in its work of leavening the dough, though its action is more rapid and effective when screened from the light.

In scriptural usage, leaven uniformly represents evil, and especially evil in its insidiously defiling character rather than in its violent aspect. Sin may act either by subtlety or by force; hence corruption and violence are the two great classes of sin (Gen. 6). Of the two corruption is more easily concealed in its working than violence, and is, therefore, fitly represented by leaven, which is corruptive of what, apart from its presence, is good and wholesome. Corinth was taught that even the presence of a little evil exerted a polluting influence upon the whole assembly.

This was early used in the fermentation of bread. As a symbol it is always used in scripture for the working of the human element, whether mind or flesh, in the things of God, and hence evil. It was strictly forbidden to be burnt in any offering made by fire (Lev. 2:11); but in the peace offering, besides the unleavened cakes and wafers, the offerer was to present leavened bread, which was to be eaten. Lev. 7:12-13; Lev. 23:17-18. Its presence here might seem to suggest an exception to the statement that leaven always signifies that form of evil; but it is not, for the peace offering typifies worship, and there, alas, the worshipper is not entirely free from indwelling sin. In the parable of 'the leaven hid in the meal,' it also represents the same evil, which in an insidious way permeates the mass with which it is mixed. The solemn words are added, "till the whole was leavened." Luke 13:20-21. It is only a too true similitude of the kingdom of God, for everywhere evil is spreading therein. In Matt. 16:6-12 leaven is applied to the teaching of the Pharisees and Sadducees. In the church, leaven when discovered must be purged out, for "a little leaven leaveneth the whole lump," 1 Cor. 5:6-8 but in the kingdom it is represented as working until all is leavened. Matt. 13:33. It is then that the King will purge out from His kingdom all that offend and commit iniquity, and cast them into a furnace of fire.

The Lord takes occasion to warn His disciples (slow indeed they are to apprehend His meaning) against the contaminating influence of the religious leaders. Leaven, as we have already had occasion to see, is a figure of an energy of evil working to corrupt. This will be found the consistent meaning of leaven throughout Scripture. Here it refers to doctrine, and in Galatians 5:9 also, where legal principles are spoken of as leaven, a little of which will mar and corrupt all the doctrine with which it is associated. The same expression in 1 Cor. 5:6 refers to the allowance of moral evil. Indifference to truth and sin will corrupt a whole company or fellowship of the people of God. In the light of scriptures like these, as well as the constant use of the term in the Old Testament, how could we think of leaven as a good influence? Not only is the simile unscriptural, but the doctrine which is built upon it is the very reverse of true. So far from good gradually permeating and changing evil, Scripture declares "evil men and seducers shall wax worse and worse, deceiving and being deceived."

The application of this to believers now is as simple as it is solemn and important. Leaven represents, as always in Scripture, the energy or activity of evil, whether displaying itself in our outward conduct, or working in the mind and desires, where it always begins, and if not detected and judged, works out in a manifest way, either in bad conduct (as with the Corinthians - compare carefully 2 Cor. 11:3 with 12:20-21), or in the way of doctrines and teachings contrary to, and subversive of, the truth. (See Gal. 5:8-10.) Hence the apostle exhorts the Corinthians to keep the feast, "not with old leaven" - their evil habits and ways before conversion - "neither with the leaven of malice and wickedness." All of this character must be entirely refused and judged in order to keep the feast. Then there is the positive side, the eating of "the unleavened bread of sincerity and truth," for thus only can it be kept.

Now the next parable is very brief, but full of meaning, First, a man sowed seed in the field, then, a man sowed mustard seed: but now we read of a woman who took leaven and hid it in the meal. The Lord's word suggests secret dealing on the woman's part; the small piece of leaven was concealed in the three measures of meal. And you know the effect of leaven is to spread itself throughout the whole mass in which it is present. The three measures of meal became permeated by the leaven. There was no further effort by the woman; the leavening process went on of itself. The woman only had to put in the leaven, and the result was sure; the whole measured quantity of meal became leavened.

Leaven is a type of evil. "Beware", said the Lord afterwards to His disciples, "of the leaven of the Pharisees." Their teaching was corrupt and corrupting. Nothing spreads so rapidly amongst the children of God as leaven. If it is introduced into a company, it spreads throughout that company: "a little leaven leavens the whole lump", the apostle said to the Corinthians (1 Cor. 5:6), and also to the Galatians (Gal. 5:9). He did not only mean that it will go on to leaven it, if not cast out. But the sentence also implies that the effect of the presence of leaven is to contaminate the whole lump, and that result is owing to the corrupting nature of the leaven itself. Unchecked evil has an insidious, permeating effect, destructive of what is good.

What then signifies "the leaven"? Does the bearing of it revert to the opening parable and its appeal to individuals? Does it not rather continue the line of the comparisons of the kingdom? Surely the latter only, setting forth the assimilating effect of a doctrine, or creed, over a certain measured sphere till it was wholly permeated. This very distinctly differs from seed with a principle of life that bears fruit, a suited and frequent figure in scripture. Never is leaven so employed elsewhere. From earliest days it symbolised a corruption that tended to work and spread, as in the Passover, authoritatively applied in 1 Cor. 5 to evil which must be purged out. By our Lord it was used to set forth the teaching of Pharisees and Sadducces, of which the disciples were to beware. Compare Gal. 5:9 for doctrine, as 1 Cor. 5 for immorality.

Here, the leaven is hidden in three measures of meal. It is a secret working of evil in that which was good; but its results were not secret, for it corrupted the whole mass very quickly. Leaven, as the Lord indicated to His disciples, denotes evil doctrine. It may not be teaching that is fundamentally unsound, heretical as we say; but a doctrine, or system of doctrines, that falsifies the whole character of Christianity.

Verse 9. "A little leaven leaveneth the whole lump." In this proverbial sentence, the weighty import of which is attested by its occurrence in two separate epistles, we are warned of the danger of entertaining in any form or measure, either doctrine or practice that is foreign to the simplicity of the Gospel… In the language of the New Testament, leaven always means something of the old and condemned nature, as opposed to the new. It is capable therefore, of a wide and varied application, and we accordingly find it so treated in the passages where it occurs. Moral iniquity and doctrinal perversion are its two chief meanings, as the occasions on which this proverb is repeated. clearly prove (cf. 1 Cor. 5:6). The Corinthian believers were endangered and defiled through their indifference to the gross moral evil which was suffered to go without condemnation or rebuke in the midst of their assembly. The Galatian churches, on the other hand, were contracting a defilement of a still more fatal kind, by consenting to doctrines which perverted, and thus destroyed, the Gospel of the grace of God. In both cases, the majesty of holiness and truth was outraged by the same means; by the admission, namely, of the old leaven under different forms. Things incongruous with Christ, and contrary to the mind of the 'Holy Spirit of God, were tolerated and accepted. Holiness was sacrificed in the one instance to a false view of Christian liberty; and in the other, truth was corrupted by human additions to the testimony of the Holy Ghost.

Leaven in Scripture is figurative of evil. Two things characterize leaven: one is, it corrupts, and the other is, it puffs up. Now both those things were most marked in the Corinthians, in which Epistle the Passover is introduced. It says they were "puffed up" (5:2). Later on it says that knowledge puffed them up, they were very proud. There was the pride of the flesh showing itself. Then it corrupts. "A little leaven leaveneth the whole lump" (v. 6) and "Evil communications corrupt good manners" (chap. 15). That which spoke of evil had to be cast out from their houses. That sets forth the holiness of the fellowship to which we are called, and in order to maintain that holiness there must be self-judgment That comes out in the 11th chapter as well as in the 5th.