The life of God, eternal life manifested and imparted. This is in John's epistle. Paul's writings present man to God in and through Christ. We must add for John's Gospel the coming of the Comforter. The reader will remark also that John's Gospel presents to us the new thing taking the place of Judaism, especially from chapter 4.
Election runs all through it, very strongly expressed.
From that, our grace and the elect remnant, the sheep alone, are recognised, and the Jews treated as reprobate. Christian life on the earth, in following a risen Christ. There are also James and Jude. Thus the Epistle of James is linked with the synagogue, and with Christians still in connection with Judaism, as we have seen them historically at Jerusalem with James at their head. The Epistle does not go beyond that position.