If you find the warning passages in Hebrews to be a challenge, you're not alone. These verses (10:26-31) pull no punches and give the reader a serious warning about the high cost of walking away from Christ. It's important, however to see these verses as embedded into a larger section of the book of Hebrews.
Hebrews 10:19-39 come immediately after a very long and extensive argument demonstrating not only the supremacy of Christ, but also the wonderful privilege we have in Christ. This argument begins in chapter 7:1 and is completed in 10:18. It is right after this that 10:19-39 come to us. It is important to see that they are composed of three parts that form a rhetorical whole:
1. Exhortation grounded upon the confidence we have from the secure access to the father that has been achieved by the son. With this confident access Christians are to…
a. Draw near in full assurance of faith
b. Hold fast the confession of hope without wavering
c. Stir up one another in love, good works, and fellowship
2. Warning about deliberately sinning – or as we saw a sinful and willful rejection of the good news that has been hammered out in these previous chapters.
a. There will not come another savior from God in which later you will find forgiveness.
b. As we have seen the major temptation that this audience faces is to return to Judaism after having declared their loyalty to Christ. So the writer to the Hebrews reminds them that for laying aside the Law of Moses there was the penalty of death – How much more, he asks, for the one who spurned the Son of God and who profaned the blood of the covenant?
c. He reminds them that it is a fearful thing to fall into the hands of the living God.
3. Encouragement in showing them the rewards of endurance in the present time.
a. He calls them to endure by remembering their past experience of God’s presence in the midst of persecution.
b. He calls them to remember that it is the Lord’s will that they endure the present trials.
c. He calls them to look forward to the great reward that awaits them in the time to come.
This pattern of exhortation, warning, and encouragement all come together to form a single argument for the early church to boldly draw near to God, hold fast to him with endurance and to encourage one another that by faith their souls may be preserved.