How important are missionaries?

Were my parents wrong? Have I been mislead? From my childhood, I've heard that every Christian should be involved in serving others and also desire to share about Christ with others. This upbringing has impacted my desire to teach about Christ in Senegal. As I reflect on what motivates me, the question arises in my mind, Does God need missionaries?

In the book of Acts, the apostle Paul confronted a group in Athens who worshiped several gods and tried to appease those gods and obligate the gods to show them favor. Paul's responds,

"The God who made the world and everything in it, being Lord of heaven and earth, does not live in temples made by man, nor is he served by human hands, as though he needed anything, since he himself gives to all mankind life and breath and everything (Acts17:24-25).

So, why does Paul tell this group God doesn't need anything and isn't served by humans, but then write letters to churches emphasizing the need to serve? Or specifically related to myself, if God doesn't need me to serve Him, why am I moving overseas? How important am I?

I think the short answer is, I'm expendable. God doesn't need me. The God who created this entire world could cause the rocks to cry out proclaiming who He is. But praise God that while He doesn't need humans, He still lets us participate. God is not requesting help because His plans require our skill sets. He is freeing us from triviality and allowing us to participate in what truly lasts.

To say it another way, everyone praises something. C.S. Lewis once said, "it's the misfits and malcontents who praise the least." Everyone instinctively praises great books, sunsets, lovers, sports teams, and so much more. We enjoy praising greatness. Now we have the privilege of praising throughout the entire world the essence of greatness, God.