Authorship of Hebrews

Origin (d. 254 AD) consistently cites in his writings that the author of Hebrews is Paul, though unsure of the penman, e.g., De Principiis, Against Celsus, To Africanus, and Commentary on Matthew, and John. Although the earliest eastern church fathers accepted Pauline authorship, some western fathers were unsure until the Councils of Hippo (393 AD) and Carthage (397 AD).
D. A. Black notes that “In the NT manuscript tradition Hebrews was always transmitted in association with the Pauline letters…” [p.3 fn. 7], and that “There is a relatively large number of words in Hebrews that are otherwise exclusively Pauline.” [p.17]
Black cites Porter and Land’s conclusion “that Luke took a discourse given by Paul in a diaspora synagogue and subsequently published it…” [p.2]

David Alan Black, The Authorship of Hebrews: The Case for Paul (Energion, 2013), and Paul and His Social Relations, eds. Stanley E Porter and Christopher D. Land (Leiden: Brill, 2013).