This week is a special thanksgiving series looking at the prayers of Paul. The hope is that if we learn what Paul was thankful for we can better recognize what we should be thankful for. You can read part one of this post here.
Paul writes to the Philippians in 1:3, 4 that he thanks God for the partnership the Philippians have with Paul. The word partnership is translated fellowship in other versions. The idea is a joint participation in a cause. In this case the joint participation is in the spreading of the gospel. Paul gave thanks to this church for aiding him in the proclamation of the gospel.