Hebrews 4:1 Therefore, let us fear if, while a promise remains of entering His rest, any one of you may seem to have come short of it.

Fear proposed only concerning those who may not have entered His rest. If-the-shoe-fits sort of statement. Adam, would you read this verse in context by including the verses just preceding?

For who provoked Him when they had heard? Indeed, did not all those who came out of Egypt led by Moses? And with whom was He angry for forty years? Was it not with those who sinned, whose bodies fell in the wilderness? And to whom did He swear that they would not enter His rest, but to those who were disobedient? So we see that they were not able to enter because of unbelief. Therefore, let us fear if, while a promise remains of entering His rest, any one of you may seem to have come short of it. Hebrews 3:16-4:1

This whole matter was based upon their ancestor’s history of unbelief. I mean, how often do we do things just because that’s the way it’s always been done in our own families, or by our own people, or by our own country? We need to have this mentality challenged in view of truth, and that’s exactly what was being done to these people in this letter. The writer stood upon the truth that they had been delivered from the bondage of the fleshly mind of their own ancestors, and here he pushed them to consider the possibility that, despite outward appearance, some of them might be in the exact same condition of unbelief. And never forget the two-sided implication found in this. For not only would it have caused the people to re-evaluate the assumption that being part of the mob equated to having believed, but it also would have caused those who did believe to question their own assumptions that everybody else viewed this miraculous life as they did.
Consider how Paul used the things that happened to unbelieving Israel in the wilderness as examples for the Corinthians. Adam, would you read 1 Corinthians 10:1-5?

For I do not want you to be unaware, brethren, that our fathers were all under the cloud and all passed through the sea; and all were baptized into Moses in the cloud and in the sea; and all ate the same spiritual food; and all drank the same spiritual drink, for they were drinking from a spiritual rock which followed them; and the rock was Christ. Nevertheless, with most of them God was not well-pleased; for they were laid low in the wilderness.

How often have we approached these examples as if they represented the experiences of fellow believers … of those who were alive from the dead? Can we not understand how Paul’s real message would be turned on its heels if these examples represented the experiences of those who were assumed to be believers? You see, that’s the whole point behind why Paul brought this in as he did. After all, who were these fathers who all experienced the same things? They were those in disobedience, those who refused the voice of God so as to not enter his rest. They were those who did not believe!

The real message to the Corinthians was a challenging of their assumptions of what it meant to live a life that was well-pleasing to God. You see, many unbelievers had crept in among their fellowship, and these religious impostors made their own evil cravings and their immoralities and their putting of God to the test and their grumbling — they packaged it in such a way as to make it all seem spiritual. In our churches today, while leaders will denounce many outwardly seeming evils, things like greed and judgmentalism flourish as if they were the foundations of Christianity itself. The message of Paul in this passage would have us reconsider all those outwardly-based assumptions of what it means to belong to Christ — things like membership, repeating the sinner’s prayer, confession, baptism, observance of communion, prosperity, having Biblical knowledge, being a pastor or teacher, etcetera. Adam, would you read 1 Corinthians 15:32-34 ?
If the dead are not raised, LET US EAT AND DRINK, FOR TOMORROW WE DIE. Do not be deceived: “Bad company corrupts good morals.” Become sober-minded as you ought, and stop sinning; for some have no knowledge of God. I speak this to your shame.

You see, the bad company Paul referred to were the unbelievers they had accepted as their peers and teachers. And no, Paul’s statement about stop sinning had nothing to do with providing a good testimony before unbelievers. That’s such BS. The tragedy was that they didn’t even recognize the difference between one who had life and one who didn’t. That’s what being sober-minded was all about. The same applies to the believing Jews who lived in and around Israel, for they too needed to become sober-minded so that they could recognize what was going on so obviously in their midst. They had assumed that all who had made a profession of the Messiah had truly believed. Their assumptions needed challenging, and they were challenged by a simple reflection upon their fathers who had not believed.

Those who can only impersonate believers only have laws, rules, and principles to offer up because they don’t have life. As we buy into their replacements for true life in Christ, we will also have to disregard Christ in those respects. The fleshly religious mind gives the impression that we are following after God by taking heed to fleshly rules and principles.

The good news did not profit their ancestors because the word they heard was not united by faith. Hebrews 4:2 The truth is that those who have believed enter that rest. Hebrews 4:3 There never was any question to this reality. The letter used the contrast between those who did believe and those who did not believe to pin-point the one difference between them. Christ, the author and finisher of our faith.

David’s reference to entering the rest — “Today if you hear His voice” — indicates that a rest still remained for the people of God in his time. We must recognize that even though Joshua had led the children into the promised land, they still had not entered God’s rest! This means that the rest of God as seen in the physical entering of the promised land was only a shadow, a type, a picture of the true rest.

God’s rest refers to his cessation of all his works of creation. The one who has entered God’s rest has also rested from his own works. It is only in Christ that we have found rest from our own works, for our life in his rest is all about the working of God in us.

Hebrews 4:11 Therefore let us be diligent to enter that rest. spoudazo primarily means make haste … hence to give diligence. It is also translated eager or make every effort. The KJV oddly translates the verse “Let us labor therefore to enter into that rest”, which seems to be a stretch. Although, I have since some years back considered a possible play on words that would have put an emphasis upon the meaning of rest. Giving more weight to the primary meaning of hurry, the play on words would be like saying hurry to slow down. You don’t actually hurry when you’re slowing down, rather it puts the emphasis upon the slowing down, as in slow down now. Ironically, when you give diligence, hurry, or labor to rest, you’re actually ceasing from your doing. A play on words could even come across as saying, If there’s one thing you should do, it’s to stop.

Who should hurry to enter that rest? Those who have not rested from their own works, the ones among the crowd who have not believed. There is no suggestion of a work to be done, nor that it is a matter of choice, rather it is a statement of reality regarding the truth of their having not yet entered God’s rest: Today if you hear his voice, do not harden your hearts. The call demands that the rest is not found in the Law, but that it is found only in Christ.

Hebrews 4:11-13 Therefore let us be diligent to enter that rest, so that no one will fall, through following the same example of disobedience. For the word of God is living and active and sharper than any two-edged sword, and piercing as far as the division of soul and spirit, of both joints and marrow, and able to judge the thoughts and intentions of the heart. And there is no creature hidden from His sight, but all things are open and laid bare to the eyes of Him with whom we have to do.

In view of those that hadn’t entered God’s rest, the truth of the living word of God exposed the false assumptions that joining a group, making a claim, or participating in Christian rituals equated to having entered that rest. See that? Everything is laid bare before him.