1 John 4:15 - Coke's Commentary on the Holy Bible

Whosoever shall confess— See on 1 John 4:2. The confession here required must have been sincere, otherwise it would have been of no moment. Confessing Jesus to be the Son of God, or the Messiah, implied their taking him for their Head and Lord, whom they were to love, imitate, and obey. Together with confession of the mouth, there was to be faith in the heart, and a suitable behaviour in the life and practice. They were to confess that Jesus isthe Christ openly and publicly, even when danger and persecution attended that confession. Hence came afterwards the distinguishing name of confessors, to denote those who had suffered in part for their religion, and who were ready to have died as martyrs, rather than to have denied the truth. Such were undoubtedly the most likely to imitate Christ's example, obey his commands, and rejoice in the prospect of his second coming. The connection of this verse with the context stands thus: It was intimated, 1 John 4:14 that the apostles had known and clearly proved, that Jesus was the Messiah and Saviour of the world. Here it is to be observed, that whoever duly attended to the evidence which the apostles had brought, and thereupon with the heart believed Jesus to be the Son of God, and lived and acted accordingly, was a true Christian, and in the divine favour: Whence St. John makes the intended inference, 1 John 4:16 namely, that whoever believed that astonishing instance of the love of God in sending his Son, would be inflamed with a just sense of it, and would sincerely love his fellow-christians. See John 17:22-23.