The scope of Jesus' work is epic.
Unlike the old sacrificial system, which required continued animal sacrifice and couldn’t in and of itself actually make anyone perfect, Christ’s sacrifice is once-for-all and truly effectual. In some way we are both perfected and being made perfect (sanctified) at the same time (cf. Heb. 10:14).
Hebrews 10:19-25 is both a comfort and an inspiration. We are encouraged that through Jesus' sacrifice, our consciences are clean, and that the confession of hope that we hold is true. We can have full assurance of the faith (cf. Heb. 10:22). I personally draw much inspiration from the exhortation in Hebrews 10:23-25 to continue on in the community of faith.
Here's where it gets sobering.
Moving through Hebrews 10:26-31 has to make you stop and think.
Those that go on sinning deliberately after receiving the knowledge of the truth (that is, the Gospel of Jesus) have nothing but judgement waiting for them.
"It is a fearful thing to fall into the hands of the living God." (Heb. 10:31)
This is indeed a terrifying passage, especially when I consider those many moments that I have deliberately chosen to sin. This came up before in chapter 6. Can you really lose your salvation?
The ESV Study Bible states that the implication here is sinning without repentance–the mark of someone who never really believed.
Maybe this is what the author is getting at when he or she talks about those that have “outraged the Spirit of grace.” (Heb. 10:29) How could you outrage the spirit of grace, except by rejecting the grace offered?
I also find it interesting that even those who reject this belief have in some sense been sanctified (cf. Heb. 10:29). The sanctification in this verse could either refer to the those that have been “set apart” in the Christian community but have rejected God’s grace (not “true believers”), or perhaps to “true believers” that have fallen away (cf. Heb. 6). Although my traditional background is fairly Reformed (beginning Southern Baptist and ending up Anglican) I am not settled on this, nor do I feel like I have to be.
Do we have to have an answer?
Instead of worrying about whether or not I can lose my salvation or if someone else is or isn’t a true believer, I’d rather concentrate on heeding this warning. No matter what, it’s not good to not be a follower of Jesus! No matter what, maybe I should have some cause for worry if I’m not following him and repenting of my sin.
I may not be able to tell if someone else is a true believer (and indeed, it’s probably not my place to judge) but I can discern the fruit of the Spirit.
Maybe that’s where our focus should be. Bearing good fruit for the Kingdom.
How important is it to conclusively know the answer to the question of whether or not we can “lose” our salvation?