To "once saved always saved" advocates, what does it mean that church leaders "keep watch over our souls"? Many evangelicals believe that people cannot lose their salvation due to disobedience. If that is so, why do we need people to "keep watch over our souls"?


  Hebrews 13:17 (ESV) Obey your leaders and submit to them, for they are keeping watch over your souls, as those who will have to give an account. Let them do this with joy and not with groaning, for that would be of no advantage to you.
Because although Christians cannot lose their salvation, they can still appear before the Lord in shame rather than in confidence (1 John 2:28). The good shepherds who watch over the flock want them to enter into the best the Lord has for them, and not be "scarcely saved" (1 Peter 4:17-18). Not all Christians will inherit a crown and rule with Christ; that belongs to the worthy. 

So the verse is about obeying the leaders so that they'll be able to give a good testimony of your conduct at the judgment seat of Christ. It appears that the Lord will weigh their words, so let them say you obeyed and not resisted, or it will go bad for you. 

For instance, if you look at 2 Peter 1:5-11, we see that continuing in sanctification leads to an abundant entrance into the kingdom. Verse 8 begins with "For if," making it conditional. Otherwise we are shortsighted and are not dealing with sin. God makes a difference, but saves both Christians.