Here are subject/purpose statements for the book of Hebrews as a whole and for each of the major sections. I divided the book into three sections according to the emphasis placed upon the role of Jesus Christ.
Subject / Purpose Statement of Hebrews as a Whole:
Jesus’ superior revelation and ministry reveals Gods purposes to and accomplishes redemption for his people, who must not neglect the redemption or reject the revelation offered through him, but must remain faithful and obedient through trials, suffering and discipline, just as their spiritual fathers did, so that they may receive the promises of God by faith before the coming Day of Judgment.
I. Jesus is the holy Prophet of Prophets who reveals the truth of God in his glorious person (1:1-4:13).
Subject / Purpose Statement: Jesus is the Holy Prophet of Prophets who reveals to his people the truth of God in the glory of His person whose word of revelation far exceeds any previous revelation, thus Jesus is exalted above previous prophets, above angels, and even above Moses, the mediator of the old covenant, so that his people reject his gracious salvation and harden their hearts against his word at their own peril.
II. Jesus is the Great Priest of Priests (Great High Priest) Who gives himself to accomplish our redemption (4:14-10:31).
Subject / Purpose Statement: Jesus is the Great High Priest who stood in place of his people, accomplishing their redemption, and who intercedes for them even now, having purchased the blessings of God for them by his obedient suffering and faithful ministry so that they must live as those who have received the blessings of a better covenant and display their faith in their confession and in their considerate care of fellow believers so that they do not live in fear of the judgment of God.
III. Jesus is the Sovereign Lord who strengthens those who trust him to endure trials (10:32-13:25).
Subject / Purpose Statement: Jesus is the Sovereign Lord over His people whose trust in Him strengthens them to endure the trials of and the discipline of their Father who will prepare them to do His will, which they must do, not rejecting his Word, or run the risk of being shaken in the final judgment and being consumed by the coming judgment of God.