Mosiah 28

The sons of Mosiah desired to be missionaries. They desired to be missionaries because "they could not bear that any human soul should perish; yea, even the very thought that any soul should endure endless torment did cause them to quake and tremble" (3). They didn't want to be missionaries because they were told to be. They wanted to become missionaries and declare the gospel because they wished to share the rejoicing in the Lord their God (2).

In the Book of Mormon Institute Manuel is says:

President Howard W. Hunter described how desire to share the gospel is a natural result of personal conversion: “A great indicator of one’s personal conversion is the desire to share the gospel with others. For this reason the Lord gave an obligation to every member of the Church to be missionaries” (The Teachings of Howard W. Hunter, ed. Clyde J. Williams [1997], 249).

Being truly converted, you are happy and joyful. You enjoy life. You are more charitable, humble, meek, obedient, faithful. Being converted truly changes you. And you really wish to share it with everyone. You want everyone to be just as happy as you are. Because you know that the gospel can give people peace, joy and comfort. If they just accept it.