I appeal to you, brothers, bear with my word of exhortation, for I have written to you briefly (Hebrews 13:22).
Is the book of Hebrews an epistle (letter) or a sermon? Commentators vary in their opinions, but it appears to be both. The fact that it is an epistle becomes clear in the final eight verses which contain the elements often found in New Testament epistles: a benediction, greetings, and an appeal asking for prayer expressing a desire to see them again (13:18-25). In verse 22, the author describes his discourse with the terms, “word of exhortation” and “brief” (literally “a few words”). Hebrews could not really be considered a brief letter, but it was not a very long sermon – it could be read in under an hour. To consider Hebrews a brief sermon, we need to set aside the modern standard for sermon length which has changed over time. Consider the account in Acts 20:7-9 which describes Paul preaching past midnight until a young man fell asleep and fell out of a third story balcony. By comparison, today the average sermon length is 37 minutes.
He calls his letter a “word of exhortation” (logou tes parakleseos). The Greek word for exhortation includes the broad ideas of warning and reproof as well as encouragement and comfort. It refers to a discourse prepared for oral delivery. The author seems to want to convey the impression that he is present with his audience in the assembly as his words are publicly read. He specifically urges his readers to “bear with” his message. Perhaps he realizes that much of what he wrote contained strong rebuke. Of course, this is not something he regrets, as he hopes his words would become the means that God would use to encourage repentance and faith; however, he does seem to understand that hard words require patience and endurance to receive. The apostle Paul wrestled with the same thoughts in 2 Cor 7:8-10.
We can learn quite a bit about the composition of a sermon by looking at Hebrews as an example. We have seen how it provides strong encouragement and assurance for the rest and hope that lie ahead for the Christian, based on the sure promises of God. At the same time, Hebrews exhorts believers to endure discipline and resist sin lest they drift away from the faith. Both the encouragement and comfort based on what God has done in Christ, and the strong warning of judgment, serve the same goal – to save those who hear. The perseverance and preservation of the saints requires encouragement as well as reproof, and if we neglect one we fail to preach the whole counsel of God which is designed to preserve us unto eternal life.