Most scholars and experts today, and since the 1800’s, do not think that Paul wrote Hebrews. This view stands in contrast to the early Christians, and up to the 1800’s, it was unanimous that Paul wrote it, even though the writer isn’t named in the book itself.
Paul was foretold to be God’s “chosen instrument to proclaim my name to the Gentiles and their kings and to the people of Israel” (Acts 9:15 NIV). So the Letter to the Hebrews falls well within this purview. Also, the complex theology and in-depth knowledge of the various details of the Old Covenant sacrificial arrangement fit Paul very well. His close friendship with Timothy, who prison release is mentioned, and the fact that the letter was written in Italy, also fit well with what we know about Paul and Timothy (13:23,24).
Why isn’t the author named in the book? None of the other theories raised for other writers, such as Apollos, or Barnabas, or Luke, or Acquilla or Priscilla, etc. have been able to explain the reason for the lack of the writer’s identification at the outset of the letter. But Paul’s is obvious!—He was hated and despised with fanatical zeal in the Jerusalem and Judea area because of his miraculous gifts of the spirit, but most importantly his gift of being able to prove that Jesus was the Messiah (Acts 9:20-30; 21:27-36; 23:12-21; 24:5-8). If Hebrews had had Paul’s name attached to it, it may not have even made it into Jerusalem. So, for good reason, it was anonymous.
However, the 2nd strongest proof of Paul’s authorship is the fact that the Chester Beatty Papyrus P46, which was written about 200 CE, includes Hebrews in its collection of Paul’s letters. In fact, Hebrews being placed after Romans as the 2nd letter, of the 9 letters that remain in the scroll, is extremely strong proof of Paul’s authorship.
But the number one proof of Paul’s authorship is something that is in conclusion of all 14 of his letters. Every writer has certain habits, and even though the style of Hebrews is somewhat different than the other 13 letters, due to the different subject matter and the situational background of the letter, this one habit of Paul marks the 14 letters as his. Let’s look at the nearly identical line that is in the conclusion of each of his 14 letters:
“The grace of of our Lord Jesus be with you”—-Romans 16:20 NIV
“The grace of the Lord Jesus be with you”—-1 Corinthians 16:24 NIV
“May the grace of the Lord Jesus Christ and the love of God, and the fellowship of the Holy Spirit be with you all”—-2 Corinthians 13:14 NIV
“The grace of our Lord Jesus Christ be with your spirit, brothers. Amen”—-Galatians 6:18 ESV
“Grace be with all who love our Lord Jesus Christ with love incorruptible”—-Ephesians 4:24 ESV
“The grace of the Lord Jesus Christ be with your spirit”—-Philippians 4:23 ESV
“I, Paul, write this greeting with my own hand. Remember my chains. Grace be with you”—-Colossians 4:18 ESV
“The grace of our Lord Jesus Christ be with you”—-1 Thessalonians 5:28 ESV
“The grace of our Lord Jesus Christ be with you all”—-2 Thessalonians 3:18 ESV
“Grace be with you”—-1 Timothy 6:21 ESV
“The Lord be with your spirit. Grace be with you”—-2 Timothy 4:22 ESV
“Grace be with you all”—-Titus 3:15 ESV
“The grace of the Lord Jesus Christ be with your spirit”—-Philemon 25 ESV
“Grace be with all of you”—-Hebrews 13:25 ESV
Every one of Paul’s 14 canonical letters has the basic phrase in the conclusion: “Grace be with you”. While Peter’s 2 letters mention grace in their conclusions, he does not use “grace” in a phrase that even comes close to the way that Paul uses “grace” in his conclusions. The fact is that none of other 7 Biblical letters’ conclusions use anything like Paul’s phrase “Grace be with you”. Along with all other Biblical evidence this fact makes it 100% certain that the Apostle Paul wrote Hebrews.