Question: "Who wrote the Book of Hebrews? Who was the author of Hebrews?"
Answer: Theologically speaking, scholars generally regard the book of Hebrews to be second in importance only to Paul's letter to the Romans in the New Testament. No other book so eloquently defines Christ as high priest of Christianity, superior to the Aaronic priesthood, and the fulfillment of the Law and the Prophets. This book presents Christ as the Author and Perfecter of our faith (Hebrews 12:2). However, both the authorship and audience are in question.
The title, "To the Hebrews," which appears in the earliest known copy of the epistle is not a part of the original manuscript. There is no salutation, the letter simply begins with the assertion that Jesus, the Son of God, has appeared, atoned for our sins, and is now seated at the right hand of God in heaven (Hebrews 1:1-4).
The letter closes with the words "Grace be with you all" (Hebrews 13:25), which is the same closing found in each of Paul's known letters (see Romans 16:20; 1 Corinthians 16:23; 2 Corinthians 13:14; Galatians 6:18; Ephesians 6:24; Philippians 4:23; Colossians 4:18; 1 Thessalonians 5:28; 2 Thessalonians 3:18; 1 Timothy 6:21; 2 Timothy 4:22; Titus 3:15; and Philemon 25). However, it should be noted that Peter (1 Peter 5:14; 2 Peter 3:18) used similar—though not identical—closings. Possibly that it was simply customary to close letters like this with the words "Grace be with you all" during this time period.
Church tradition teaches that Paul wrote the book of Hebrews, and until the 1800s, that issue was closed. However, though a vast majority of Christians—both and scholars and the laity—still believe Paul wrote the book, there are some tempting reasons to think otherwise.
First and foremost is the lack of a salutation. Some sort of personal salutation from Paul appears in all of his letters. So it would seem that writing anonymously is not his usual method; therefore, the reasoning goes, Hebrews cannot be one of his letters. Second, the overall composition and style is of a person who is a very sophisticated writer. Even though he was certainly a sophisticated communicator, Paul stated that he purposely did not speak with a commanding vocabulary (1 Corinthians 1:17; 2:1; 2 Corinthians 11:6).
The book of Hebrews quotes extensively from the Old Testament. Paul, as a Pharisee, would have been familiar with the Scripture in its original Hebrew language. In other letters, Paul either quotes the Masoretic Text (the original Hebrew) or paraphrases it. However, all of the quotes in this epistle are taken out of the Septuagint (the Greek Old Testament), which is inconsistent with Paul's usage. Finally, Paul was an apostle who claimed to receive his revelations directly from the Lord Jesus (1 Corinthians 11:23; Galatians 1:12). The writer of Hebrews specifically says that he was taught by an apostle (Hebrews 2:3).
If Paul didn't write the letter, who did? The most plausible suggestion is that this was actually a sermon Paul gave and it was transcribed later by Luke, a person who would have had the command of the Greek language which the writer shows. Barnabas is another likely prospect, since he was a Levite and would have been speaking on a subject that he knew much about. Martin Luther suggested Apollos, since he would have had the education the writer of this letter must have had. Priscilla and Clemet of Rome have been suggested by other scholars.
However, there is still much evidence that Paul wrote the letter. The most compelling comes from Scripture itself. Remember that Peter wrote to the Hebrews (that is, the Jews; see Galatians 2:7, 9 and 1 Peter 1:1). Peter wrote: "...just as our dear brother Paul also wrote you with the wisdom that God gave him [emphasis added]" (2 Peter 3:15). In that last verse, Peter is confirming that Paul had also written a letter to the Hebrews!
The theology presented in Hebrews is consistent with Paul's. Paul was a proponent of salvation by faith alone (Ephesians 2:8, 9), and that message is strongly communicated in this epistle (Hebrews 4:2, 6:12, 10:19-22, 10:37-39, and 11:1-40). Either Paul wrote the epistle, or the writer was trained by Paul. Although it is a small detail, this epistle makes mention of Timothy (Hebrews 13:23), and Paul is the only apostle known to have ever done that in any letter.
So, who actually wrote Hebrews? The letter fills a needed space in Scripture and both outlines our faith and defines faith itself in the same way that Romans defines the tenets of Christian living. It closes the chapters of faith alone and serves as a prelude to the chapters on good works built on a foundation of faith in God. In short, this book belongs in the Bible. Therefore, its human author is unimportant. What is important is to treat the book as inspired Scripture as defined in 2 Timothy 3:16-17. The Holy Spirit was the divine author of Hebrews, and of all Scripture, even though we don't know who put the physical pen to the physical paper and traced the words.