The Epistle to the Hebrews (abbr. Heb for citations) is a very consciously "literary" document in the New Testament. The purity of its Greek was noted by Clement of Alexandria, according to Eusebius of Caesarea (Historia Eccl., VI, xiv), and Origen asserted that every competent judge must recognize a great difference between this epistle and Paul's (Eusebius, VI, xxv).
The letter has carried its traditional title since Tertullian described it as
Barnabae titulus ad Hebraeos in
De Pudicitia chapter 20 ("Barnabas's Letter to the Hebrews").
More...