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There is some debate by scholars about this but the majority feel that it was written by Paul. The most common explanation for the lack of direct identification of the author within the epistle itself is that Paul, having become notorious among the Jews as a prominent member of their community who converted to Christianity, did not wish to prejudice his Jewish readers against his earnest arguments by having them encounter his name in the epistle. Also, some of the differences in style to other of Paul's epistles may be accounted for by the fact that the original would have been written in Hebrew and translated into Greek, perhaps by Luke.
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