Galatians 5:9-10

9People say this: ‘Only a small amount of yeast in the flour will cause a loaf of bread to grow big.’

10But I feel sure about you, because we belong to the Lord. I know that you will agree with what I say about this. But as for the man who is confusing you, God will punish him. It does not matter who he is, God will punish him.