Galatians 5:9

A little leaven leaveneth the whole lump.
] A proverbial expression pretty much in use with the Jews; see ( 1 Corinthians 5:6 ) , respecting either persons or things; and is in answer to, or prevents an objection that might be made, or something that might be said, in favour of these churches; that their case was not so bad, or the danger they were in so great, as was represented by the apostle; since they were only a few persons that propagated this notion, and but few that received it, at least thoroughly gave into it; and that, if it was an error, it was but a small one, and only regarded a single ritual, or a few rituals of the law; to which the apostle replies, by supposing, but not granting this to be the case, since they were pretty generally declined, and the error was not a slight one, that as a little sour leaven influences and ferments a large mass, or lump of dough, and makes it of the same nature with it, so a small error in doctrine, as it may be thought to be, increases to more ungodliness, and eats as doth a canker; and though a few hands may be first concerned in propagating it, and but few be infected with it, yet these may soon spread the contagion through the whole society: wherefore errors and false teachers should be nipped in the bud, and stopped in their beginnings, how inconsiderable soever they and their tenets may be judged to be.