Hebrews 12:15 in the World English Bible
looking carefully lest there be any man who falls short of the grace of God, lest any root of bitterness springing up trouble you and many be defiled by it,
Context
14 Follow peace with all men, and holiness, without which no man shall see the Lord:
15 Looking diligently lest any man fail of the grace of God; lest any root of bitterness springing up trouble you, and thereby many be defiled;
16 Lest there be any fornicator, or profane person, as Esau, who for one morsel of meat sold his birthright.