Paul is writing this letter from prison. The two groups of people he’s writing about here both preach Christ, but it’s their motives & attitudes that are starkly different. One group preaches Christ in a righteous & noble fashion. Their love for Paul is real, and they understand fully that he is “In chains for Christ.” The other group is envious of Paul’s stature and following, even from prison…and respond negatively to his success. Yes, they do preach Christ in a fashion, but it’s out of self-seeking duplicity…and a vying for power & prestige. To them, preaching Christ has become a competition… and a spreading of dissension among the brethren.