2 Corinthians 6:1 (NKJV)
There is a big difference between working with someone and working for someone. Working with someone implies shared effort and responsibility, what is being done is a collaboration of abilities and resources. Working with someone means that a person is not alone and has someone else helping them get things done. When you are working for someone that carries with it the thought of one person giving direction and another person carrying out the plan that was given to them. Usually when you work for someone the main effort comes from one person and responsibility is given from one person to another.
In both letters to the Corinthians Paul talked about being a worker together with God. Paul realized that what he was doing was in partnership with God. Paul was not trying to figure out everything on his own and just relying on his own ability. Paul knew that it was God that had called him and it was God that would help him. Paul understood, just as we should, that the only way to really fulfill God's plan is with God's help. Yes, Paul did talk about being a bondservant of God in many of his letters but Paul also knew that whatever He did for God he was doing with God.
We can be sure that no matter what God might call us to do He will be there to help us. We never want to fall into the trap of thinking that what we do depends solely on our ability and our coming up with the best plan on our own; we need to develop a trust and reliance on God. This is the difference in Christianity, we do serve our God but He works with us as well. Other religions focus on man working for and serving some god but there is no cooperation with a distant and often harsh deity. But we are children of God who can always rely on our heavenly Father to be there and work with us in anything and everything that needs to be done. We are workers together with God!