Hebrews 3

Hebrews 3:5-6:
Now Moses was faithful in all God’s house as a servant, to testify to the things that were to be spoken later, but Christ is faithful over God’s house as a son. And we are his house if indeed we hold fast our confidence and our boasting in our hope

Merely saying or declaring that one is a Christian amounts to very little. In fact, it may be an act of self-delusion and self-deception. All through the NT we come across what can only be called “false faith”. False faith is a form of “belief” in Christ that never fully takes root in the heart. There may be an initial season of joy and excitement and Bible study and church attendance, but it is followed, at some point, by drifting away from the Lord and falling into unrepentant sin and idolatry.

Perseverance functions as evidence of an existing right relationship with God. Our author doesn’t say in v. 6 that a person will become a part of God’s people if they persevere. Neither does he say that a person will remain a part of God’s people if they persevere. Rather he says: this is how you can know if someone already is a part of God’s people – does he or she hold fast their confidence and their boasting in hope in Christ all the way to the end. In other words, he is less concerned with whether or not they profess to believe and more with whether or not they persevere to believe.

Some so stress God’s saving grace that they end up undermining personal responsibility and holiness of life. People are told: “If you ever prayed a prayer or walked an aisle or wept during a hymn or signed a decision card or joined in with your friends at summer camp in confessing the name of Jesus aloud, you are saved and secure no matter what else you do in life.” People who have wandered away and are living in unrepentant sin and give no indication of a deep heart-felt affection for Jesus and his saving death on the cross are often told, “Don’t worry. Once saved, always saved. Your decision back then is all that matters.”

At the other end of the spectrum are those who minimize and undermine God’s saving grace by arguing that it really doesn’t matter what happened in the past, even if at some point you were genuinely born again and justified by faith in Christ. You must remain faithful and if you don’t your failure will nullify God’s grace and cut you off forever from his saving purposes. You may have once been genuinely saved but now, because you have abandoned your faith, you forfeit that privilege and fall under condemnation yet again.

Both are wrong!

Look closely at the latter half of the verse where he refers to our “confidence” in Christ and our boasting in the “hope” we have in him. Clearly he is describing the initial act of faith when a man or woman claims to have put their trust in Jesus for salvation. If a person who professes to have “confidence” in Christ, a person who claims to have trusted him for salvation, “holds fast” in this hope and faith all the way to the end, this indicates that they truly “are” members of God’s “house.” Perseverance provides evidence of the reality of one’s claim to know Jesus.

How can we know whether or not someone genuinely shares in Christ, which is to say, is born-again and is justified and is a child of God? We can know by observing whether or not they “hold fast” their confidence and hope in Christ.

He does not say that if you fail to hold fast your confidence this means you once had it but later lost it. Rather, if you fail to hold it, it means you never had it at all. If someone does not hold firmly to the end of this “faith” or “confidence” that he/she claims to have put in Christ, this reveals that they never truly and sincerely shared in Christ in the first place.

Simply put, perseverance is the proof of salvation. No perseverance, no salvation; not because you had it but lost it, but because you never had it at all. So let me say it again as clearly as I can. Our author is not telling us what will be true if a person endures to the end but rather what is already true. A person’s endurance or perseverance in faith and obedience is the evidence of their vital, saving connection to Christ and their participation in him.
--Sam Storms: No Perseverance, No Salvation

Hebrews 3:7-11:
“Therefore, as the Holy Spirit says: Today, if you hear his voice, do not harden your hearts as in the rebellion, on the day of testing in the wilderness, where your fathers tested me, tried me, and saw my works for forty years. Therefore I was provoked to anger with that generation and said, ‘They always go astray in their hearts, and they have not known my ways.’ So I swore in my anger, ‘They will not enter my rest.’”

The writer of Hebrews quotes from Psalm 95 and attributes the words to the Holy Spirit. Together, the psalmist and the voice of Yahweh make it clear that if the punishment for disobedience of the law was severe, then the penalty for rejection of the gospel would be far worse. -Rob Phillips; The Pathway

Hebrews 3:19:
So we see that they could not enter in because of unbelief.

Even though the people of Israel saw the waters of the Red Sea divide and they walked over on dry ground, the moment they got thirsty, their hearts were hard against God and they did not trust him to take care of them. They cried out against him and said that life in Egypt was better.
That is what this verse is written to prevent. O how many professing Christians make a start with God. They hear that their sins can be forgiven and that they can escape hell and go to heaven. And they say: “What have I got to lose? I'll believe.”
But then in a week or a month or a year or ten years, the test comes — a season of no water in the wilderness. A weariness with manna, and subtly a growing craving for the fleeting pleasures of Egypt, as Numbers 11:5–6 says, “We remember the fish which we used to eat free in Egypt, the cucumbers and the melons and the leeks and the onions and the garlic, but now our appetite is gone. There is nothing at all to look at except this manna.”
This is a terrifying condition to be in — to find yourself no longer interested in Christ and his Word and prayer and worship and missions and living for the glory of God. And to find all fleeting pleasures of this world more attractive than the things of the Spirit.
If that is your situation, I plead with you to listen to the Holy Spirit speaking in this text. Give heed to the Word of God. Do not harden your heart. Wake up to the deceitfulness of sin. Consider Jesus, the apostle and high priest of our great confession, and hold fast to your confidence and hope in him.
And if you have never even made a start with God, then put your hope in him. Turn from sin and from self-reliance and put your confidence in a great Savior. These things are written that you might believe and endure, and have life.
--John Piper