The Writing of the Epistle
The Epistle of James probably was written shortly before the Jerusalem Conference, most likely just before, that is, about A.D. 48 or 49. There is no room here for an extended discussion of the proof of this statement. In general I agree with the arguments of Mayor on this point.[25] Plummer[26] is unable to decide between A.D. 49 and 59. Writers like von Soden place it at the end of the century, and Bruckner puts it in the second century. Spitta admits that Paul in Romans alludes to the Epistle of James, but suggests that the present epistle is a Christian adaptation of a Jewish book.
On the whole, the weight of the argument is toward the conclusion that James wrote the epistle before the Conference and without reference to the Judaizing controversy. Paul in Galatians and Romans may very well have in mind a misuse of what James in chapter 2 says about faith and works, which misapprehension he seeks to correct. The epistle must be placed either between A.D. 40 and 50, before the Judaizing controversy arose, or in the middle of the second century, after it had died down.[27] The early date has the best of it, in my opinion.
If this date for the writing of the epistle is correct, we have no difficulty in seeing how James could have written it so early. Already about A.D. 44 we saw his leadership in the Jerusalem church (Acts 12:17). No man in the apostolic circles at this period had the ear of the Jewish Christians as did James. This is seen further in the fact that he is asked to preside over the Conference in Jerusalem to settle the issues raised by the Judaizers against the work of Paul and Barnabas among the Gentiles. The epistle, therefore, seems to come in at this state of the career of James and is the chief expression left of his mind and life.