Disciples of Jesus Christ throughout the ages have followed His mandate: “Go ye into the world, and preach the gospel to every creature” (Mark 16:15). Members of The Church of Jesus Christ of Latter-day Saints—sometimes inadvertently called the Mormon Church—believe they are still obligated to obey this commandment today. Teachings in the Doctrine & Covenants—a book of scripture in The Church of Jesus Christ that contains modern revelations—echo this. “And this gospel shall be preached unto every nation, and kindred, and tongue, and people” (Doctrine & Covenants 133:37). In the early days of The Church of Jesus Christ, men left their wives and children to preach to gospel to the nations of the world. Today, young men and young women leave their families to do the same.
Elder Russell M. Nelson, a member of the Quorum of the Twelve Apostles (with the First Presidency, the governing body) of The Church of Jesus Christ said:
Missionaries in their late teens or early 20s are young in ways of the world. But they are blessed with gifts—such as the power of the Holy Spirit, the love of God, and testimonies of the truth—that make them powerful ambassadors of the Lord. They share the good news of the gospel that will bring true joy and everlasting happiness to all who heed their message. And in many instances they do so in a country and a language foreign to them. 
This Generation is Prepared
As members of The Church of Jesus Christ, I have had many discussions with my children about serving proselytizing missions. When I asked my 12-year-old son why youth served missions, he simply said, “To preach the gospel of Jesus Christ.” To him, much in life is cut-and-dry. He knows right from wrong, and he stands up for what is right. Prophets and apostles have told us that this generation of youth are prepared for this day—this time in the history of the world. Elder Neil L. Andersen, an Apostle of Jesus Christ, spoke to young men ages 12-25 who hold the priesthood of God (the priesthood is the authority and power given to men by God to act in all things necessary for the salvation of His children). His words apply to young women as well as young men:
Have you ever thought about why you were sent to earth at this specific time? You were not born during the time of Adam and Eve or while pharaohs ruled Egypt or during the Ming dynasty. You have come to earth at this time, 20 centuries after the first coming of Christ. The priesthood of God has been restored to the earth, and the Lord has set His hand to prepare the world for His glorious return. These are days of great opportunity and important responsibilities. These are your days.
With your baptism, you declared your faith in Jesus Christ. [To the young men] With your ordination to the priesthood, your talents and spiritual capacities have been increased. One of your important responsibilities is to help prepare the world for the Second Coming of the Savior. 
I need look no further than my own children to see the truth of this statement. My oldest came to this earth with a mind and a will of his own. Sometimes our discussions would end up in a power struggle. But he was given a priesthood blessing (given by the laying on of hands, by one who is in authority, to heal the sick or bring comfort or counsel to the one seeking help) that changed everything. In this blessing, he was told that he was given the gift of stubbornness, to stubbornly and steadfastly stand up for what is right. And he does. He is the first to tell his sisters to be modest, and he taught his younger brother to be modest. He decided to get up at 5 a.m. during the school year so that he could study the scriptures and pray without interruption. (I’ll be the first to admit that he didn’t get that one from me—I am not an early riser.) The others came with their own powerful gifts and talents, ones that will serve them well in defending and building up the kingdom of God. The depth of their understanding is amazing and, as a parent, humbling to behold.
The Modern Stripling Warriors—Youth Defending What is Right
In the Book of Mormon: Another Testament of Jesus Christ, a companion scripture to the Bible and a record of God’s dealings with peoples who lived in the ancient Americas— there is a story about 2,000 remarkable young men. Their fathers had been wicked and bloodthirsty, but embraced the gospel of Jesus Christ when it was taught to them. They buried their weapons of war as a covenant to God and a symbol of their repentance. But years later, their protectors—a group of people known as the Nephites—were under attack by their enemies, the Lamanites. When they saw the afflictions that their protectors were enduring, they wanted to help and were ready to take up their arms. Helaman—a righteous military leader—and others persuaded them to not violate their covenant with God. Elder M. Russell Ballard, of the Quorum of the Twelve Apostles, recounts this “powerful and instructive story” from the book of Alma:
The scriptural account doesn’t tell us who first pointed out that their sons had not made the same covenant their parents had made. I like to think that it was one of the young men who suggested the possibility that he and his peers be allowed to “take up arms, and [call] themselves Nephites.” …
This was an extraordinary task for a group of 2,000 young men, but they were extraordinary young men. According to the scriptural record: “They were exceedingly valiant for courage, and also for strength and activity; but behold, this was not all—they were men who were true at all times in whatsoever thing they were entrusted.
“Yea, they were men of truth and soberness, for they had been taught to keep the commandments of God and to walk uprightly before him” (Alma 53:20–21).
The rest of the story tells how these young men fought valiantly against the much older and much more experienced Lamanite army. According to their leader, Helaman, “They … fought as if with the strength of God; … and with such mighty power did they fall upon the Lamanites, that they did frighten them; and for this cause did the Lamanites deliver themselves up as prisoners of war” (Alma 56:56).
Imagine that! These inexperienced young men were so spiritually and physically prepared, and so powerful, that they frightened their foes into surrendering! Although all 2,000 of the young men were wounded in battle at one time or another, not one was killed (see Alma 57:25). Again quoting Helaman, “And we do justly ascribe it to the miraculous power of God, because of their exceeding faith in that which they had been taught to believe—that there was a just God, and whosoever did not doubt, that they should be preserved by his marvelous power” (Alma 57:26). 
These 2,000 young men were called Helaman’s Stripling Warriors. The youth of today are modern stripling warriors. For members of The Church of Jesus Christ, partaking of the sacrament (the ordinance of partaking of the bread and water in remembrance of the Savior’s atoning sacrifice) each Sunday is a time to renew the covenants we made at baptism to take upon ourselves the name of the Savior, Jesus Christ, and follow Him in all things. In a ward (or congregation), the young men ages 12-15 who hold the priesthood pass the sacrament. Males who are 16 and older bless the sacrament. For a year or so, our little ward had few young men and no deacons (12- and 13-year-olds). Gradually, between boys turning 12 and boys moving in, we now have about 8 young men—most of them deacons. When these young men are together in a room, there is an almost tangible power that they exude. Not a power of arrogance or pride, but a power of righteousness and humility of those who seek only to follow their Savior, Jesus Christ.
The Power of Sisters
When the young women in our ward are together, there is a similar feeling. They do not hold the priesthood, but they honor those who do. They also seek to follow the Savior in all things. As sisters in the Church and as sister missionaries, these young ladies are a powerful force for good. President Gordon B. Hinckley, the late president of The Church of Jesus Christ, said:
We need some young women [to serve as sister missionaries]. They perform a remarkable work. They can get in homes where the elders cannot. … (“To the Bishops of the Church,” Worldwide Leadership Training Meeting, June 2004, 27)
He also said:
Many mission presidents give their sister missionaries credit for being more effective than the elders in opening doors and minds to the teaching of the gospel. One mission president told me, perhaps facetiously, that if he had four pairs of sister missionaries doing the finding and the teaching, he could keep a pair of elders busy doing the baptizing. 
As Mormon missionaries, young men and young women are powerful ambassadors for the Lord. They are young but they have been prepared from the foundation of the world for their role in this time period in the history of mankind—the role of preparing the world for the Second Coming of the Savior, Jesus Christ. They love our Heavenly Father and His Son, Jesus Christ, and seek to do Their will. And they will be blessed for their service. Elder Nelson said:
The decision to serve a mission will shape the spiritual destiny of the missionary, his or her spouse, and their posterity for generations to come. A desire to serve is a natural outcome of one’s conversion, worthiness, and preparation.