1 Corinthians 5:6

4 In the name of our Lord Jesus Christ, when ye are gathered together, and my spirit, with the power of our Lord Jesus Christ,

5 To deliver such an one unto Satan for the destruction of the flesh, that the spirit may be saved in the day of the Lord Jesus.

Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump?

7 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:

8 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.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
Your boasting is not good. Do you not know that a little leaven works through the whole batch of dough?
KJV
Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump?
WEB
Your boasting is not good. Don’t you know that a little yeast leavens the whole lump?
ASV
Your glorying is not good. Know ye not that a little leaven leaveneth the whole lump?
DARBY
Your boasting [is] not good. Do ye not know that a little leaven leavens the whole lump?
BLB
Your⁺ boasting [is] not good. Do you⁺ not know that a little leaven leavens the whole lump?
ÅB
Det er ikke smukt det som dere roser dere av. Vet dere ikke at en liten surdeig syrer hele deigen?
OTB
Deres skryt er ikke fordelaktig. Vet dere ikke at en liten surdeig påvirker hele deigen?
B1930
Det er ikke smukt det som I roser eder av. Vet I ikke at en liten surdeig syrer hele deigen?

Study notes (Tyndale)

Original text and word study

Cross references