D&C 4 is short, but every single verse means something.
God's work is going forth.
Serve God will all your heart, might, mind a strength.
If ye have a desire, ye are called to the work.
The field is white, and ready to harvest.
You are qualified for the work if you have faith, hope, charity, and an eye single to God's glory.
Remember faith, virtue, knowledge temperance, patience, brotherly kindness, godliness, charity, humility and diligence.
Ask and ye shall recieve; knock and it shall be opened unto you.
(Before Superman left on his mission, he got a picture of himself in his suit in the middle of a wheat field. This isn't it, but the best likeness I could find on google.)
Just about covers all the gospel, eh?
Some things that have always stood out to me:
• Simply having a desire, not a letter from the prophet, calls you to the work
• Faith, hope, charity and an eye single to God's glory qualify you. Once you are called, (by simply that desire) you must work to develop these key elements to be a profitable servant.
• Among all the virtues mentioned, a few stood out to me. Temperance. Knowledge. Diligence. All things I need to work on.
So I guess I can't say, "I'd do missionary work if I didn't live in Utah. If I only KNEW people who weren't members." That implies that I have the desire, but not the opportunity. Which isn't true. If I have a real desire, God will provide opportunities.