Hebrews 12:15-17 NKJV
(15) looking carefully lest anyone fall short of the grace of God; lest any root of bitterness springing up cause trouble, and by this many become defiled; (16) lest there be any fornicator or profane person like Esau, who for one morsel of food sold his birthright. (17) For you know that afterward, when he wanted to inherit the blessing, he was rejected, for he found no place for repentance, though he sought it diligently with tears.