Paul.
Heb 10:34 For you both
had compassion on me in my chains, and joyfully accepted the
plundering of your possessions, knowing that you have for yourselves a better possession and an enduring one in the heavens.
That subject, that Christianity is superior to Judaism, is a favorite one with Paul (compare 2 Corinthians 3:6-18 ; Galatians 3:23-25 ; Galatians 4:1-9 Galatians 4:21-31).
Christ appears in Hebrews 1:3 cf Philippians 2:6 of the Deity. His lowering of Himself for man's sake similarly, compare Hebrews 2:9 exaltation, compare Hebrews 2:8 1 Corinthians 15:25 1 Corinthians 15:27 compare Hebrews 8:6 represented as the sacrifice for sin prefigured by the Jewish sacrifices, compare Romans 3:22-26 ; 1 Corinthians 5:7.
The phrase, "God of Peace," is peculiar to Paul, compare Hebrews 13:20 ; Romans 15:33; 1 Thessalonians 5:23 (Margin), 1 Corinthians 12:4 appears in Hebrews 11:7 ; 10:38 Romans 1:17 ; 4:22 ; 5:1 ; Galatians 3:11 ; Philippians 3:9.
Christians are children needing milk, that is, instruction in the elements, whereas riper Christians, as full-grown men, require strong meat, compare Hebrews 5:12 Hebrews 5:13 ; 6:1 Galatians 4:9 ; Colossians 3:14.
Boldness of access to God by Christ, compare Hebrews 10:19 Romans 5:2 ; Ephesians 2:18 ; 3:12 compare Philippians 1:30 ; Colossians 2:1.
Hebrews 12:1 service, Romans 9:4 bondage, Hebrews 2:15 Paul's style appear in this Epistle; namely, a propensity "to go off at a word" and enter on a long parenthesis suggested by that word, a fondness for play upon words of similar sound, and a disposition to repeat some favorite word.
Frequent appeals to the Old Testament, and quotations linked by "and again," compare Hebrews 1:5 ; Hebrews 2:12 Hebrews 2:13 Romans 15:9-12 Hebrews 2:8 quoted in a form not agreeing with the Septuagint, and with the addition "saith the Lord," not found in the Hebrew, in Hebrews 10:30 ; Romans 12:19.
The personal notices all favor its Pauline authorship, namely, his intention to visit those addressed, shortly, along with Timothy, styled "our brother," Hebrews 13:23 his formerly having been imprisoned in Palestine, according to English Version reading, Hebrews 10:34 to them from believers of Italy, Hebrews 13:24 the name may be the rhetorical character of the Epistle which led the author to waive the usual form of epistolary address.
JFB - Introduction
Well, that and the title page in my bible says "The Epistle of Paul to the Hebrews."