My favorite missionary in the scriptures is Ammon. He goes to teach the Lamanites and has enormous success. He talks about the work like this (paraphrased):
My brothers and sisters were suffering, but the Lord has brought them his everlasting light. They are circled by his unending, matchless love - a love that is generous and perfect. And we, the missionaries, have been instruments in the hands of the Lord to make this thing happen.Of course, the next question is, "How can I be an instrument in the hands of the Lord?" It's a good question, but very personal.
I think that as I've gotten older, I tend to grow in my dislike towards assuming that I know what God wants. The world is weird and so many things are "messed up." The only way for me to make sense of it is to quit thinking that I know what God wants. I don't.
He's given commandments - which are general, and callings - which are personal. Some of my callings are from my church leaders, others are... a lot more difficult to pinpoint. I feel really drawn towards my Czech ancestors, as if it were a calling. I am confident that it is good for me to spend my time and effort in studying all things related to my Czech ancestors. Nobody specifically pulled me aside and told me that was my calling, but it doesn't really matter; I feel called.
I feel like as long as we are working towards keeping the commandments - both the broad ones and the more personal ones, like our personal and church callings - that is the best way to be an instrument in his hands. I think that if you try to be an instrument in his hands, you're actually more likely to fail. It's like putting your eye on the wrong mark. Instead of focusing on the things that God has already given you, you're focusing on what you think of and how you interpret God's plan. There's too much variability in that.
But there isn't variability in striving to keep the commandments. It's like... focusing on the commandments allows for some degree of flexibility. The commandments can change as our situations change. Some very basic human commandments (don't steal! don't lie! don't commit adultery!) aren't likely to change. But my identity, my role, my piece in God's plan, well, it has flexibility because I am a changing, evolving, growing human being.
In order to be an instrument in God's hands, I need to try my best to keep the commandments. That means following my church leaders, trying to fulfill my callings, and continually seeking inspiration and direction from God about what my callings even are.