For if we willfully persist in sin after having received the knowledge of the truth, there no longer remains a sacrifice for sins, but a fearful prospect of judgment, and a fury of fire that will consume the adversaries. Anyone who has violated the law of Moses dies without mercy "on the testimony of two or three witnesses." How much worse punishment do you think will be deserved by those who have spurned the Son of God, profaned the blood of the covenant by which they were sanctified, and outraged the Spirit of grace? For we know the one who said, "Vengeance is mine, I will repay." And again, "The Lord will judge his people." 31 It is a fearful thing to fall into the hands of the living God.
2 Peter 2:20-21
20 For if, after they have escaped the pollutions of the world through the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and overcome, the latter end is worse for them than the beginning.
21 For it would have been better for them not to have known the way of righteousness, than having known it, to turn from the holy commandment delivered to them.
It is impossible for those who have once been enlightened, who have tasted the heavenly gift, who have shared in the Holy Spirit,
5 who have tasted the goodness of the word of God and the powers of the coming age
6 and who have fallen away, to be brought back to repentance. To their loss they are crucifying the Son of God all over again and subjecting him to public disgrace.
7 Land that drinks in the rain often falling on it and that produces a crop useful to those for whom it is farmed receives the blessing of God.
8 But land that produces thorns and thistles is worthless and is in danger of being cursed. In the end it will be burned.