Hebrews 10:26-31 (New International Version)
If we deliberately keep on sinning after we have received the knowledge of the truth, no sacrifice for sins is left, but only a fearful expectation of judgment and of raging fire that will consume the enemies of God.
Anyone who rejected the law of Moses died without mercy on the testimony of two or three witnesses.
How much more severely do you think a man deserves to be punished who has trampled the Son of God under foot, who has treated as an unholy thing the blood of the covenant that sanctified him, and who has insulted the Spirit of grace?
For we know him who said, "It is mine to avenge; I will repay", and again, "The Lord will judge his people".
It is a dreadful thing to fall into the hands of the living God.
ANOTHER TRANSLATION:
Hebrews 10:26-31 (The Message)
If we give up and turn our backs on all we've learned, all we've been given, all the truth we now know, we repudiate Christ's sacrifice and are left on our own to face the Judgment—and a mighty fierce judgment it will be!
If the penalty for breaking the law of Moses is physical death, what do you think will happen if you turn on God's Son, spit on the sacrifice that made you whole, and insult this most gracious Spirit?
This is no light matter.
God has warned us that he'll hold us to account and make us pay.
He was quite explicit: "Vengeance is mine, and I won't overlook a thing" and "God will judge his people."
Nobody's getting by with anything, believe me.