This is not the first time faith or its opposite, unbelief, is mentioned in Hebrews. The very purpose of the entire epistle is to recapture, build, and sustain in its recipients their faith in the superiority of Jesus Christ Himself and in His message, the gospel of the Kingdom of God.
Notice the strong, earlier statements Paul makes regarding unbelief:
» Hebrews 3:12, 19: Beware, brethren, lest there be in any of you an evil heart of unbelief in departing from the living God. . . . So we see that [the Israelites in the wilderness] could not enter in[to the Promised Land] because of unbelief.
» Hebrews 4:2: For indeed the gospel was preached to us as well as to them; but the word which they heard did not profit them, not being mixed with faith in those who heard it.
These are weighty statements. The Israelites failed to accomplish their responsibility of walking from Egypt to the Promised Land primarily because of one weak element in their character. They did not believe God or His messenger Moses. They did not listen thoughtfully or yieldingly.
Because of the warning contained within Hebrews 10:35-39, chapter 11 places the virtue of faith in direct contrast to the sin of unbelief by exposing what unbelief caused to occur. The Israelites drew back in fear rather than trusting God and boldly going forward. Thus, the main point of the epistle of Hebrews is that they will be destroyed who, by failing to put their trust in the living God, shrink back from this Christian war we have been called to fight, whereas those who believe will be saved.