Hebrews 10:26-31 For if we sin willfully after we have received the knowledge of the truth, there no longer remains a sacrifice for sins, but a certain fearful expectation of judgment, and fiery indignation which will devour the adversaries. Anyone who has rejected Moses' law dies without mercy on the testimony of two or three witnesses. Of how much worse punishment, do you suppose, will he be thought worthy who has trampled the Son of God underfoot, counted the blood of the covenant by which he was sanctified a common thing, and insulted the Spirit of grace? For we know Him who said, "Vengeance is Mine, I will repay," says the Lord. And again, "The LORD will judge His people." It is a fearful thing to fall into the hands of the living God.
Hebrews 6:4-8 For it is impossible for those who were once enlightened, and have tasted the heavenly gift, and have become partakers of the Holy Spirit, and have tasted the good word of God and the powers of the age to come, if they fall away, to renew them again to repentance, since they crucify again for themselves the Son of God, and put Him to an open shame. For the earth which drinks in the rain that often comes upon it, and bears herbs useful for those by whom it is cultivated, receives blessing from God; but if it bears thorns and briers, it is rejected and near to being cursed, whose end is to be burned.
Matthew 12:31-32 “Therefore I say to you, every sin and blasphemy will be forgiven men, but the blasphemy against the Spirit will not be forgiven men. Anyone who speaks a word against the Son of Man, it will be forgiven him; but whoever speaks against the Holy Spirit, it will not be forgiven him, either in this age or in the age to come.
Hebrews 2:1-3 Therefore we must give the more earnest heed to the things we have heard, lest we drift away. For if the word spoken through angels proved steadfast, and every transgression and disobedience received a just reward, how shall we escape if we neglect so great a salvation, which at the first began to be spoken by the Lord, and was confirmed to us by those who heard Him,
Numbers 15:30-31 'But the person who does anything presumptuously, whether he is native-born or a stranger, that one brings reproach on the LORD, and he shall be cut off from among his people. Because he has despised the word of the LORD, and has broken His commandment, that person shall be completely cut off; his guilt shall be upon him.’”
Mark 3:29 but he who blasphemes against the Holy Spirit never has forgiveness, but is subject to eternal condemnation"
Deuteronomy 30:17-19 But if your heart turns away so that you do not hear, and are drawn away, and worship other gods and serve them, I announce to you today that you shall surely perish; you shall not prolong your days in the land which you cross over the Jordan to go in and possess. I call heaven and earth as witnesses today against you, that I have set before you life and death, blessing and cursing; therefore choose life, that both you and your descendants may live;
1 John 5:16 If anyone sees his brother sinning a sin which does not lead to death, he will ask, and He will give him life for those who commit sin not leading to death. There is sin leading to death. I do not say that he should pray about that.
2 Peter 2:20-22 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. 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. But it has happened to them according to the true proverb: 'A dog returns to his own vomit,' and, 'a sow, having washed, to her wallowing in the mire.'