Hebrews 12:15-17

See to it that no one falls short of God’s grace; that no root of resentment springs up and causes trouble, and by it many be defiled; and [see to it] that no one is immoral or godless like Esau, who sold his own birthright for a single meal. [Gen 25:29-34] For you know that later on, when he wanted [to regain title to] his inheritance of the blessing, he was rejected, for he found no opportunity for repentance [there was no way to repair what he had done, no chance to recall the choice he had made], even though he sought for it with [bitter] tears. [Gen 27:30-40]