Hebrews 6: 4 For it is impossible to restore again to repentance those who have once been enlightened, who have tasted the heavenly gift, and have shared in the Holy Spirit,  and have tasted the goodness of the word of God and the powers of the age to come,  if they then fall away, since they are crucifying once again the Son of God to their own harm and holding him up to contempt.  For land that has drunk the rain that often falls on it, and produces a crop useful to those for whose sake it is cultivated, receives a blessing from God.  But if it bears thorns and thistles, it is worthless and near to being cursed, and its end is to be burned.
What are the qualities mentioned in verses 4 and 5 if not qualities of real believers?
I have a relative who used to be a preacher. He preached every week while his wife visited her family in another city. At least he thought that is what she was doing. She was seeing a non-family member as well. And it wasn’t for worship. When my relative found out he bottomed out and when he finally got back on his feet he did not want God to come with him. His own testimony is that he never had, even while he was preaching, what he was preaching about. Is it really possible that a man who preached the truth and pastored people can not be in possession of what he is trying to give to others? The Scriptures’ testimony is that it is indeed the case.
Most of the warnings in the Epistles have to deal with teachers and teachings that are present in the church. John speaks about Diotrephes who loves to put himself first and speaks wicked nonsense, (III John 9-10). Timothy is warned about teachers who speak confidently about things they know nothing about (I Tim. 1:1-7), and those who have an appearance of godliness but deny its power (II Tim. 3:1-5). Both Peter and Jude have blistering attacks against those who are teaching in the church but are very wicked (II Peter 2 and Jude 5-13).
But the most scathing indictment regarding false believers in the pulpit comes from the mouth of Jesus Himself in Matthew 7:21-23. There He speaks of those who can testify to having worked miracles, cast out demons and preached the Truth and yet are refused entry into the Kingdom of heaven because Jesus never knew them. That means that even when they were doing those things they were not known by God in any saving sense.
Texts such as these are reminders to us to not be fooled by appearances. The fact that such people eventually leave the faith is no testimony of people losing their salvation. It is testimony that even very wicked people can look good for awhile. Even very wicked people can convince the gullible that evil is good and good is evil. They may even be able to perform a miracle. But that never means that they are to be followed or that they are even trusting Christ themselves.
Paul warns the Thessalonians that some will be able to perform counterfeit miracles that deceive those who are perishing (II Thessalonians 2:9-12). And if not for the keeping power of God even the chosen of God would be drawn away into being deceived by them (Mark 13:22). There is much that can be said about these things and about such people. The point right now is that Hebrews 6:4 is not talking about saved people. The overall teachings of the New Testament is that people can look very good and very godly and still not be truly converted. They have the worst kind of deception – the deception of self. The beauty behind this distressing news is this:
2 Tim. 2:19 (ESV) But God’s firm foundation stands, bearing this seal: “The Lord knows those who are his,” and, “Let everyone who names the name of the Lord depart from iniquity.”
God is never deceived. God makes no mistake. He cannot be fooled that someone really knows Him if he does not. Do not allow what you see in people to make you contradict the Scriptures. The Bible is abundantly clear that when God determines to save someone, that someone is going to be saved and changed and persevere in the faith. It is also clear that many will look like believers who are not. The fact that some fall away is a testimony to the truth of the Bible. It should make us very diligent in working out our salvation in fear and trembling and it should make us sing for joy that God has done what no amount of human effort can accomplish.
Having a right relationship with God is not a matter of working miracles or preaching great sermons (or bad ones, for that matter) or being in a big church or a host of other things that people think matter. Jesus Christ died on the cross to take the punishment that others deserve. All who come to Him in faith and repentance will be forgiven and saved from the punishment that they deserve. Jesus rose from the dead. Those who trust Him will rise as well. Because He rose, those who are trusting Him have a living Saviour who lives to intercede for them before the Father. This means that Jesus represents us in the councils of glory so that our sins do not condemn us.
The reason people are saved is that God honours the work of His Son. His death for us means that our sins have been dealt with. Because we trust Him we are credited with having the very righteousness of Jesus just as He was counted as having our sins. He sees us as righteous as Jesus is. No amount of good things done by us can cause that to happen. That is pure grace.
People may be able to behave righteously for a time. They may be able to deceive others into thinking they are true believers. They may be able to convince themselves of it. But they can never cause God to see them as having the very righteousness of Christ. Only He can do that. It is a stunningly glorious thought and it is a great shame that people miss it for a sad counterfeit. Don’t be one of them.