And not just contemporary biblical scholars.
It was recognised by a few of the early church fathers - those fully conversant in Greek - that the sophisticated vocabulary, wordplays and syntax of
Hebrews do not fit Paul's writing style.
Indeed, the church father Origen actually said according to Eusebius: "
But who wrote the epistle, in truth God knows” (
Hist. Eccl. 6.25.11-14).
Origen also wrote:
That the character of the diction of the epistle entitled To the Hebrews has not the apostle’s rudeness in speech, who confessed himself rude in speech, that is, in style, but that the epistle is better Greek in the framing of its diction, will be admitted by everyone who is able to discern differences of style. But again, on the other hand, that the thoughts of the epistle are admirable, and not inferior to the acknowledged writings of the apostle, to this also everyone will consent as true who has given attention to reading the apostle…. But as for myself, if I were to state my own opinion, I should say that the thoughts are the apostle’s, but that the style and composition belonged 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 handed it down as Paul’s. But who wrote the epistle, in truth God knows. Yet the account which has reached us [is twofold], some saying that Clement, who was bishop of the Romans, wrote the epistle, others, that it was Luke, he who wrote the Gospel and the Acts.
It is virtually impossible, based on the Greek, for Paul to have written this homily (its structured as a homily more than an Epistle).