They Contaminate the Church
A little leaven leavens the whole lump of dough. (5:9)
A third characteristic of the false teachers was that they contaminated the church, spreading their heresy among both true believers and would-be believers. Just as a little leaven leavens the whole lump of dough, so a small amount of falsehood can corrupt the thinking and living of a large group of people.
In Scripture, leaven often represents sin directly, as in Jesus’ warning about “the leaven of the Pharisees and Sadducees,” which referred to their false teaching (Matt. 16:6, 12). But the figure of leaven is generally used simply to indicate permeating power, whether of something good or evil. In this passage, as in his reference to the gross immorality of the Corinthians, Paul used the figure of leaven in both ways, as representing the actuality of sin as well as its power to infect and permeate that which is good (see 1 Cor. 5:6).
Just as a single cell of cancer can metastasize until it spreads throughout the physical body, a single false doctrine can multiply itself and spread throughout a body of believers. A great forest fire can be started by one spark. “For want of a nail the shoe was lost,” wrote Benjamin Franklin; “for want of a shoe the horse was lost; for want of a horse the rider was lost; and for want of a rider the battle was lost.”
9. A little leaven. This refers, I think, to doctrine, not to men. It guards them against the mischievous consequences which arise from corruption of doctrine, and warns them not to consider it, as is commonly done, to be a matter attended by little or no danger. Satan’s stratagem is, that he does not attempt an avowed destruction of the whole gospel, but he taints its purity by introducing false and corrupt opinions. Many persons are thus led to overlook the seriousness of the injury done, and therefore make a less determined resistance. The apostle proclaims aloud that, after the truth of God has been corrupted, we are no longer safe. He employs the metaphor of leaven, which, however small in quantity, communicates its sourness to the whole mass. We must exercise the utmost caution lest we allow any counterfeit to be substituted for the pure doctrine of the gospel.
9 Paul now quotes a proverbial saying (cf. 1 Co 5:6) to indicate the insidious character of the Judaizers’ “different gospel” (1:6). The inherent danger for the Galatians in this teaching is that as it is taken in, it may permeate their faith and become a corrupting, evil influence that not only perverts the truth but will come to control their lives (cf. Mk 8:15). Paul warns the Galatians again, by implication, to avoid evil consequences by resisting the false message of the Judaizers.
9 In what appears to be a proverbial saying (cf. 1 Cor. 5:6b) Paul further illustrates the definitely evil character of the Judaizers’ teaching: “a little yeast ferments the whole lump of dough.” “Proverbial in form, but not found outside Paul as a proverb, these words might have been associated in the Christian church with the parable of the leaven [Mt. 13:33; Lk. 13:21],” but a direct relation is not apparent. In any event, the saying “goes rather beyond the thought and usage of the Jewish festival [of Unleavened Bread]. It is a generally valid saying, an illustration of the truth of experience that little causes can have great effects.”95
It is difficult to say whether “leaven” refers to the false teachers or to their teaching; possibly in favor of the latter is the use of “leaven” for the hypocrisy of the Pharisees (Lk. 12:1) and the teaching of the Pharisees and Sadducees (Mt. 16:6, 11f.). Moreover, the emphasis in v. 8 is clearly not so much on the individual as on his “persuasion.” However, the unity of teaching and person can be recognized and the situation adequately explained if we say: “The doctrine of the necessity of circumcision, insidiously presented by a few, is permeating and threatening to pervert the whole religious life of the Galatian churches.”
9 Paul applies a bit of proverbial wisdom to demonstrate that the rival teachers and their influence represent a danger to the entire Christian enterprise in which the Galatians are engaged: “a little yeast leavens the whole lump” (5:9). The proverb is effective, since everyone would be familiar, given the ubiquitous practice of baking bread, with how a small amount of leaven (the ancient equivalent of a sourdough starter) gets worked into the whole lump of flour and makes the whole lump puff up equally (transferring the sour smell of fermentation also equally throughout the lump).87 Paul no doubt wants the connotations of corruption and souring to be transferred and applied to the rival teachers’ influence; if he was effective in demonstrating the divergences between God’s plan and the teachers’ advice, he will be successful here as well.
Paul uses this same proverb in 1 Cor 5:6 to talk about the corrosive effects of one shameless sinner on the moral fabric of the entire community. A little shamelessness in regard to sin in one small pocket of the community has the power to erode the entire community’s sensitivity to sin and to God’s ethical standards. So here, being persuaded by the rival teachers on a small point (e.g., the necessity just of circumcision, let alone obeying the whole Torah) or allowing their influence to take hold in a small pocket of the church would lead to the reintroduction of slavery to the whole.
Its harmful effects would spread (v. 9)
Paul’s warning in verse 9 that ‘A little yeast works through the whole batch of dough’ is also heard in 1 Corinthians 5, where the concern is with the defiling effects of an immoral man on the whole congregation. Such a man needs to be removed. Here in Galatians 5 the proverb is used in connection with harmful teaching. If the teaching isn’t stopped, it will eventually damage the entire church.
False teaching, in other words, is subject to the same law that governs yeast. Its harmful effects spread. What a melancholy witness is borne to that truth throughout church history! That is why false teaching must be given no quarter. Teaching that robs us of our liberty in Christ and threatens to enslave us again is too dangerous to be tolerated. Its tendency is to spread and harm more and more people. At the earliest possible opportunity it must, if possible, be stopped.
5:9 / The saying “a little yeast works through the whole batch of dough” is found also at 1 Corinthians 5:6. It appears to have been common in the ancient Greek-speaking world to use yeast as a symbol for evil’s powerful corrupting capacity (cf. Mark 8:15). In this case Paul is warning that even though there may be only a few advocating circumcision their influence could damage the nature of the Galatian churches.
9. A little leaven—the false teaching of the Judaizers. A small portion of legalism, if it be mixed with the Gospel, corrupts its purity. To add legal ordinances and works in the least degree to justification by faith, is to undermine “the whole.” So “leaven” is used of false doctrine (Mt 16:12: compare Mt 13:33). In 1 Co 5:6 it means the corrupting influence of one bad person; so Bengel understands it here to refer to the person (Ga 5:7, 8, 10) who misled them. Ec 9:18, “One sinner destroyeth much good” (1 Co 15:33). I prefer to refer it to false doctrine, answering to “persuasion” (Ga 5:8).
Ver. 9.—A little leaven leaveneth the whole lump (μικρὰ ζύμη ὅλον τὸ φύραμα ζυμοῖ); a little leaven leaveneth the whole kneading. This proverb is cited again in precisely the same words in 1 Cor. 5:6, with the words prefixed, “know ye not that.” In both passages the leaven is an element of evil, and so also in Matt. 16:11; but our Lord applied it also to an element of good, which was to penetrate (apparently) the whole mass of humanity (Matt. 13:33). What has the apostle precisely in his view as the leaven in the present instance? In 1 Cor. 5:6 it is unchastity, which, if once tolerated in a Church, especially amid so licentious a population as that of Corinth, would be but too likely to impregnate balefully the sentiment of the whole community. And here likewise, as there, the leaven does not appear to denote, as some have supposed, the individuals in whom some noxious element was conspicuous, but that noxious element itself; namely, to judge from the colouring of the immediate context, the “readiness to hearken” to “another gospel,” which was promising comfort and sense of acceptance, more or less, in the practice of at least some of the outward ordinances of Judaism. This leaven had already begun to work, embodying itself in the observance, pedantically and ostentatiously, of the days and feasts of the Jewish calendar (ch. 4:10). Now, a movement of mind manifesting itself in some form of external religionism, when once it begins to show itself in a Christian community, has a great tendency to spread. For always, in every Church, there are unstable souls, too often not a few, never able to come to the knowledge of the truth; which have never truly discerned Christ’s all-sufficiency for their spiritual needs, or have lost any superficial persuasion of it once enjoyed; and which, consciously unsatisfied with what they as yet possess, and nevertheless only toying with spiritual things, are ready to adopt almost any novelty of religious behaviour offering itself for their acceptance. The particular form in which the external religionism of seekers after another gospel clothes itself varies according to varying tastes or circumstances. Among the Galatian Christians such persons were now beginning to feel attracted by that venerable kind of outward piety exhibited by devout or professedly devout Jews; but in their own practice committing the fatal blunder of mistaking the external shows of saintliness for the reality of saintliness, and but too willing to make the former serve in lieu of the latter. The danger of the leaven spreading was, in the present case, increased by the instability of character and the quick impulsiveness belonging to the Celtic temperament. The true antidote to this “leaven” is in every age the same; namely, that which the apostle in this Epistle strives to administer—the gospel of the righteousness and Spirit of Christ crucified.
9 μικρὰ ζύμη ὅλον τὸ φύραμα ζυμοῖ, “ ‘a little yeast leavens the whole batch of dough.’ ” The occurrence of these exact words in 1 Cor 5:6, introduced by the epistolary formula οὐκ οἴδατε (“do you not know”) and the quotation formula ὅτι (“that”), suggests that both there and here Paul is using a proverbial saying having to do with the tendency of small matters to become large concerns and so to dominate a given situation. In 1 Cor 5:6 the proverb has to do with an incestuous man whose conduct had the potential of corrupting the whole Corinthian church. Here it has to do with a false theology that was perverting the Galatian churches. While in one of Jesus’ parables the leavening influence of yeast is compared positively to “the kingdom of heaven/God” (Matt 13:33//Luke 13:21//Gos. Thom. 96), most often in the NT and antiquity yeast was used figuratively as a negative symbol for the penetrating and corrupting influence of evil (cf. Mark 8:15, par.; 1 Clem 5.6; Ignatius, Mag. 10.2; Plutarch, Quaest. Rom. 109 [2.289F]; Justin, Dial. 14.2.3; Ps. Clem. Hom. 8.17).
9. The warning continues, this time in the form of a proverbial saying, found also in 1 Cor. 5:6: A little leaven leavens the whole lump. Seemingly insignificant causes can lead to momentous consequences, whether for good (as in Matt. 13:33) or for evil, as in the present case. Principles penetrate! When a person has forsaken the sound principle of salvation by grace alone through faith (the latter considered as God’s gift; see N.T.C. on Eph. 2:8), and has taken his stand on a new “persuasion,” namely, salvation by grace plus works, the attention is gradually shifted to works, until grace has disappeared completely, and so has Christ, on whom grace rests. Illustrations of the penetrating power of evil: a. In ancient Israel the deceptively innocent worship of Jehovah under the symbolism (and by means) of an image soon led to gross idolatry; b. it took only a “worm” to destroy Jonah’s “gourd” (Jonah 4:7); c. cancer spreads (metastasizes), so that a malignant tumor, ever so small in its beginning, may in the end destroy the entire body (cf. 2 Tim. 2:17); d. a “little” (?) carelessness starts a forest-fire, with destruction of thousands of valuable lumber-producing trees, or sets fire to a hotel, killing several people; e. someone tosses a few roots of a “beautiful” flower into a stream; result: many of the rivers, canals, lakes, and bayous of beautiful Florida, etc., are choked with the water hyacinth, which menaces wildlife, causes floods, strangles navigation, costs a fortune in attempts at eradication, so far with no completely satisfactory remedy in sight; and f.:
“For want of a nail the shoe was lost; for want of a shoe the horse was lost; for want of a horse the rider was lost; for want of a rider the battle was lost; and for want of a battle the kingdom was lost. All this for want of a horseshoe nail” (Benjamin Franklin, according to one version).
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