the one do it of love, knowing that I am set for the defence of the gospel;
Verse 16. The one preach Christ of contention. So as to form parties, and to produce strifes among his professed followers. Not sincerely. Not purely--αγνως--not with pure motives or intentions. Their real aim is not to preach Christ, but to produce difficulty and to stir up strife. They are ambitious men, and they have no real regard for the welfare of the church and the honour of religion.
You might stumble thinking that if this doctrine were truly of God, He would not cast His instrument aside like a broken vessel. But a strange chemistry of Providence extracts great good from great evil: the gospel advances though I am confined, for the word of God cannot be imprisoned as my body is.
AI summary
Commenting on Philippians 1:12-20
The oldest manuscripts transpose these verses, and read, "These (last) indeed out of love (to Christ and me), knowing (the opposite of 'thinking' below) that I am set (that is, appointed by God, Th1 3:3) for the defense of the Gospel (Phi 1:7, not on my own account).