Paul was imprisoned, and Christians who were self-willed and non-spiritual were preaching the Gospel. Possibly they thought that would frustrate Paul, but he wrote:
15 Some, to be sure, are preaching Christ even from envy and strife, but some also from good will;
16 the latter out of love, knowing that I am appointed for the defense of the Gospel;
17 the former proclaim Christ out of selfish ambition, rather than from pure motives, thinking to cause me distress in my imprisonment.
18 What then? Only that in every way, whether in pretense or in truth, Christ is proclaimed; and in this I rejoice, yes, and I will rejoice. (Phil 1:15-18)
The message is more important than the motives. Sometimes we forget that it is the information contained in the Gospel that saves people, not our sincerity. If we were perfectly sincere all the time with wonderful motives, it would be nice. But we will never fully arrive at that condition. So instead of worrying about our motives when we share the Gospel, we should be much more interested in seeing how the Gospel when it is heard and believed by another changes that person's life. Our lives should adorn the Gospel, but it is the Gospel which is the most important and not our well-adorned lives.