What does Hebrews 6:9 mean?
Prior verses included a severe warning. After criticizing those who are lazy in their approach to Christian truth (Hebrews 5:11–14), the author resolves to move on to deeper ideas, even if some are not ready (Hebrews 6:1–3). Before this, he discusses the dire consequences of falling into doubt and disobedience (Hebrews 6:4–8). Instead of pressing forward with such an ominous tone, the writer switches to reassurance before resuming his teaching.Although the consequences of "falling away" are extreme, the writer of Hebrews does not necessarily expect that everyone reading these words is in immediate danger of that fate. The point of giving his alert was just that: a loving, pre-emptive warning. Based on the evidence of their lives, there was good reason to think that they could move past their immaturity while continuing to serve God in faith.
Just as in Hebrews 5:9, immediate context determines which aspect of "salvation" is in mind here. The prior context is anchored in the example of Israel in the wilderness: disobedience leading to a loss of inheritance, and to judgment (Numbers 13—14). Chapter 5 reminded us of Christ's example, in order to obtain this same type of "salvation" by obedience. Specifically, this is the idea of sanctification, or a gradual growth in Christ-like behavior. In this verse, just as in Hebrews 5:9, the term does not refer to heaven or hell, but to our conduct and character.
Another useful observation from this passage is that spiritual immaturity is not incompatible with good works. It is possible for a Christian to serve God well, and with sincerity, and yet still be stuck in spiritual immaturity. The danger presented by that condition exists even if the Christian's lifestyle is godly.