But recall the former days when, after you were enlightened, you endured a hard struggle with sufferings, sometimes being publicly exposed to reproach and affliction, and sometimes being partners with those so treated. For you had compassion on those in prison, and you joyfully accepted the plundering of your property, since you knew that you yourselves had a better possession and an abiding one. Therefore do not throw away your confidence, which has a great reward. For you have need of endurance, so that when you have done the will of God you may receive what is promised. For,
“Yet a little while, and the coming one will come and will not delay; but my righteous one shall live by faith, and if he shrinks back, my soul has no pleasure in him.”
But we are not of those who shrink back and are destroyed, but of those who have faith and preserve their souls. (Hebrews 10:32-39, ESV)
Though our author has given a very stern warning to those who “shrink back” from following Christ and treat his sacrifice as worthless, it is not his opinion that his addressees are of that ilk. He must warn them just in case, because a servant of God must always follow the Lord in His desire to warn the world of His judgment. Just as Yahweh sent Jonah to Nineveh to warn them of impending doom, knowing they would repent at the warning, so He has sent our author to write to this congregation and warn them lest there be any among them who are unclear about the consequences of rejecting the faith.
The evidence the author of Hebrews has that this congregation of Christ followers are genuine followers after all is the affliction they endured for becoming Christ followers and how they endured it with the assurance that this world was not their final home but a better one awaited them, an eternal one. They didn’t throw away their confidence then, so he doesn’t believe they will throw away their confidence now, though it has been a temptation.
When someone we know acts like an unbeliever but we have seen evidence in their lives and behavior that they know the Lord, we may need to speak to them about the consequences of not knowing the Lord in order to call them back to their senses. True believers will respond and be called back. Unbelievers, who only embrace Christianity in a surface way, will not repent. God uses our warnings, our admonitions made in love, to separate the wheat from the chaff. Our confrontations are part of His disciplinary action.
Professor Williams received yellow beauty rose bulbs and planted them and cared for them. As the plant grew he watched eagerly for the flower. If the flower had been red, when might Professor Williams have assumed that the flower stopped being a yellow beauty rose? If it bloomed yellow, was it a yellow beauty rose, being yet only a bulb?