The writer makes that clear when he says in Hebrew 2:1, “[The message] was declared first by the Master, and it was attested to us by those who heard.” This means that the writer is a second-generation believer, yet he writes like an apostle, like someone in authority, and he transmits apostolic tradition. For example, he says, “In the days of his flesh, Jesus offered up prayers and supplications, with loud cries and tears” (Hebrews 5:7). That’s an eyewitness report, something our author could have obtained from one of the Master’s original disciples, such as Simon Peter. The writer of the Epistle to the Hebrews speaks with an apostolic voice that we would not expect from a second-generation disciple unless he was of distinguished rank and well-recognized as an authority, one who comes from the Pauline circle, and one who knows believers from Italy (see Hebrews 13:24.)
The early church had many opinions about the authorship. The absence of a superscription leaves it anonymous. The early church wanted it to be an epistle of Paul. Some codices bundled it with Paul’s letters, but this document is not Paul’s style or language. The epistle is written in excellent Greek, unlike Paul’s. The theological concepts of Hebrews are not particularly Pauline. Moreover, Paul considered himself the apostle to the Gentiles, but the epistle to the Hebrews appears to be written to Jewish disciples of Yeshua.
Nevertheless, it seems that the epistle was written by someone within the Pauline entourage. One bit of evidence for this hypothesis is that the author makes reference to Timothy having been released from imprisonment and waiting for his arrival. Timothy was Paul’s chief disciple. The Hebrews author’s close relationship with Timothy puts him into Paul’s company. The second century church writer Origen addresses the authorship of Hebrews this way:
But as for myself, if I were to state my own opinion, I should say that the thoughts are the apostle’s [i.e. Paul’s], but that the style and composition belong to one who called to mind the apostle’s teachings and, as it were, made short notes of what his master said. If any church, therefore, holds this epistle as Paul’s, let it be commended for this also. For not without reason have the men of old time handed it down as Paul’s. But who really wrote the epistle, in truth, only God knows. (Origen, Homilies on Hebrews, quoted in Eusebius, Ecclesiastical History 6.14.1–4)
Some early church writers had the tradition that Paul’s colleagues, Luke the doctor or Clement of Rome, might have been involved in the composition. Modern speculations include Barnabas, Apollos, and even Priscilla (see Acts 18:2, 3) but there is no evidence or ancient tradition to support these theories.
Clement of Alexandria had a tradition that Paul’s travelling companion Luke wrote the epistle, translating it from an Aramaic document originally composed by Paul: “For as Paul had written to the Hebrews in his native tongue, some say that the evangelist Luke, others that this Clement himself, translated the epistle." (Eusebius, Ecclesiastical History 3.38:2)
One of many problems with Lukan authorship is that the Greek does not sound like Luke’s, nor does it betray any hint of having been translated from a Semitic original. The fourth-century bishop of Caesarea, Eusebius, cites the Lukan-Pauline theory, but he also notes an alternative tradition which suggests that Clement of Rome might have been involved in the composition.
The bishop Eusebius cites a tradition that Clement was the author of the epistle:
Others claim that it was Clement himself. This seems more probable because the epistle of Clement and that to the Hebrews have a similar character in regard to style, and still further because the thoughts contained in the two works are not very different. (Eusebius, Ecclesiastical History 3.38:2–3)
Modern scholars disagree with that assessment. They do agree that the style sounds similar, and at points, identical, but they explain the similarities by arguing that Clement was imitating the style of the Epistle to the Hebrews. Scholars also object to the theory that Clement wrote the epistle on the basis that the theology of the epistle is completely different than Clement’s. Whereas the book of Hebrews teaches the cancellation of the Temple and the sacrificial system, the First Clement seems to regard that system as a worthy model for churches to emulate with respect to Ecclesiastical authority. On this basis, most scholars say that the same writer could not have written both First Clement and the Epistle to the Hebrews.
This opinion is based on presuppositions arising from an incorrect theological perspective on the Temple and priesthood. Hebrews does not need to be read as teaching the cancellation of the Temple and the Levitical system. Once this perspective on the book is adopted, then Clement of Rome is a possible and even likely candidate. His authorship is backed up by a strong historical tradition and by similarity of thought and style between Hebrews and other Clementine epistles.