Adam Clarke on 1 Corinthians 5:6

Your glorying is not good - You are triumphing in your superior knowledge, and busily employed in setting up and supporting your respective teachers, while the Church is left under the most scandalous corruptions - corruptions which threaten its very existence if not purged away.

Know ye not - With all your boasted wisdom, do you not know and acknowledge the truth of a common maxim, a little leaven leaveneth the whole lump? If this leaven - the incestuous person, be permitted to remain among you; if his conduct be not exposed by the most formidable censure; the flood-gates of impurity will be opened on the Church, and the whole state of Christianity ruined in Corinth.