The letter to the Hebrews was as the title suggests written to Jewish Christians. It contains many admonitions for them to accept Christ as the Messiah and His law as being superior to the Law of Moses. Christ and the church are compared/contrasted with Moses and the Children of Israel.
It is not known who authored this letter, but several individuals have been suggested as possible writers. Some of those mentioned are Paul, Apollos, Barnabas, Luke, Silas, Clement, Mark, Aquila and Priscilla. Many of the writers of the second and third centuries concluded for various reasons that the author of Hebrews was the Apostle Paul. A detailed discussion of this subject is recorded in New Testament Commentary on Hebrews by R. Milligan, pp. 5-18.
Several historians have agreed that the epistle to the Hebrews was written from Rome in A.D. 63 about the time that Paul was released from prison.