But the other of love
Those that were truly brethren in the Lord, who had received the grace of God in truth, to whom the Gospel was come in power, and who had a spiritual and experimental knowledge of Christ, and of the mysteries of his grace; these preached Christ of love, "out of the love of him", as the Ethiopic version reads; that is, out of love to Christ, who to them was exceeding precious, altogether lovely, the chiefest among ten thousands, and their hearts being hot and burning with love to him, they therefore spoke of him with their tongues; and out of love to the Gospel of Christ, which with them was the pearl of great price, and every truth of it more valuable than gold, silver, and precious stones; and out of love to the church of Christ and the members of it, that their souls might be fed and nourished with the wholesome words of Christ, might be comforted with the doctrines of grace, and be established and built up in their most holy faith; and out of love to the souls of others, knowing their miserable estate by nature, and the danger they were in, and therefore preached Christ as the only way of salvation, whereby they could escape the wrath to come; and out of love to the apostle likewise, which the following clause shows;
knowing that I am set for the defence of the Gospel;
meaning either that they knew he was a chosen vessel, to bear the name of Christ, and preach his Gospel in the world; that he was ordained and appointed a minister of it before the world was; separated to it from his mother's womb, and was called unto, and sent to preach it by Christ, and was set apart for it by the church; and was in a very eminent manner qualified to defend it, by preaching, disputing, writing, and suffering: or that they knew that he was laid, or lay, as the words may rendered, in prison, for defending the Gospel of Christ; yea, they knew that his lying in prison was in defence of the Gospel; and therefore, out of love to him, they joined issue with him to defend the Gospel; as he by suffering for it, so they by preaching it, which they knew full well would be matter of great joy to him.