Things like repentance, belief, cleanliness, resurrection, and eternal judgement—these are all basic, foundational aspects of Christianity. They are not signs of mature believers. There are deeper teachings to understand beyond them. Paul’s believing Hebrew friends have wandered from the path of maturity and need to repent and return to that path or risk losing blessings. The window of repentance does not stay open indefinitely.
Some believers squander the immense benefits of the gift of salvation and live in rebellion to God. They fall away from their faith. This does not undo their justification before God, but it ruins their walk and fellowship with God. It is impossible to bring some of these believers back to repentance once the window of repentance closes. This is why Paul is urging immediate repentance.
Christians are expected to obey God and produce faithful works, which leads to blessings from Him. Some Christians rebel and waste the grace given to them, living lives that are useless and harmful to themselves and others. They will not receive blessings from God.
Paul is convinced the window of repentance is still open for his friends. He thinks his readers are capable of maturity and faithfulness. He has already seen them show love to God by ministering to other Christians. Paul wants them to realize God will reward them, and that they should be diligent in growing mature. Faith and patience are key to inheriting God’s blessings.
God keeps His word. He blesses those who are patient and obedient, like Abraham. This should encourage Christians to pursue maturity. The blessings of living faithfully are a certainty, guaranteed by God.
Jesus is the only priest we need. Like Melchizedek, He is both king and priest, eternal, righteous, who brings peace and blessings. He is the source of our hope, which should keep us from drifting from our faith.
Paul wants his audience to grow up as believers. They already know the basic elements of Christianity, and they need to mature in their faith. Paul believes his readers are capable of maturity, but he warns them that some believers wander away from God and lose blessings. He emphasizes how faithful God’s word is, and that He blesses His children who are obedient toward Him and become mature.