One might ask, "where does this desire for the salvation of mankind come from?" Why weren't the sons of Mosiah content to preach the gospel to their own people and attend to their church duties like everyone else? The answer comes from their great desire for their fellow beings. This desire is one of the greatest expressions of charity that can be demonstrated. Their concern was not for themselves or their own people; they were worried about the salvation of the Lamanites. They were about to find out that it would take all the characteristics of charity to be successful in such a bold endeavor. Indeed, they would be required to suffer long, be kind, envy not, be humble, behave not unseemly, seek not their own, nor be easily provoked (see 1 Cor 13:4-5).
The sons of Mosiah teach us that missionary work is one of the most beautiful expressions of charity. The pure love of Christ extends to every creature on the face of the earth with the corresponding desire to do that which will be of greatest worth for both the missionary and his people. President George Albert Smith prayed that all the saints would have this kind of charity.
George Albert Smith
"Missionary work requires sacrifice. I pray that the Spirit of God may burn in the bosoms of the Latter-day Saints; that the love and charity our Father has for his children may be ours; that we may rejoice when we see his children understanding the truth and that we may be willing to make what may sometimes be termed a sacrifice; that we may be willing to make the investment to bless our kind, going forth with all our might to bring light and salvation to the children of men by preaching unto them the restored gospel of our Lord." (Conference Reports, June 1919, p. 44)