Php 1:15-18, 15 Some indeed preach Christ from envy and rivalry, but others from good will. 16 The latter do it out of love, …17 The former proclaim Christ out of selfish ambition, …18 What then? Only that in every way, whether in pretense or in truth, Christ is proclaimed, and in that I rejoice. Yes, and I will rejoice
There are groups as mentioned that made it their mission to hurt Paul and his ministry through envy, jealousy, rivalry, selfish ambitions etc. These preached Christ from impure hearts. Their motive was to depreciate Paul’s preaching and exalt their own. Paul notes them such and highlights those like him who preached Christ out of love.
As long as Christ and His true doctrine was preached, Paul rejoiced because Christ is exalted in true preaching of His word regardless of the motives behind the preaching. Paul would rather have false brethren proclaim the true word than true brethren proclaim false doctrine. Paul rejoiced in the good God brings out of evil. He would not allow the bitterness of his opponents to define how to respond, his joy would continue knowing that in spite of the present hindrances, the result was assured. The actions of self-seekers turned into the good man’s source of joy.