What does Hebrews 3:16 mean?

Verses 16 through 18 use a series of rhetorical questions—sentences which are framed as questions, but are really meant as definite statements. These are used to prove the author's main point, which is that believers who fail to trust in God risk losing their spiritual blessings. Just as Israel suffered forty years of wandering when they were faithless, so too can a Christian suffer instead of obtaining the "Promised Land" of God's inheritance. This is not a matter of salvation, but of fellowship, and yet it is still deadly serious.

This verse also shows that the Bible's authors understood the use of generalities. The words say "all" in reference to those who left Egypt. However, a major aspect of the story was the faithfulness of Joshua and Caleb, and the fact that the younger members of Israel would live to enter Canaan. The point, however, fits the rhetoric. This is similar to how we might say, "nobody shops at that store anymore" when business is extremely poor. The point is not literalism, but effect, and would have been well understood by the Jewish readers of this letter.

This verse also gives one of the four major types of spiritual failure which can invite divine discipline. The first, given here, is rebellion. This is from the Greek word parepikranan, and it most literally means to "provoke." These are those moments when we respond to God in a way which even other human beings would consider obnoxious or immature. Complaining, selfishness, carelessness, and so forth are all forms of rebellion.