John Wesley on Hebrews 12:15

Looking diligently, lest any one - If he do not lift up the hands that hang down. Fall from the grace of God: lest any root of bitterness - Of envy, anger, suspicion. Springing up - Destroy the sweet peace; lest any, not following after holiness, fall into fornication or profaneness. In general, any corruption, either in doctrine or practice, is a root of bitterness, and may pollute many.