For dozens of reasons, Christ has asked His disciples to preach His gospel and to share His words with all of God's children. As we take this opportunity to become missionaries, our lives are forever changed. However, as Elder W. Christopher Waddell taught in October 2011, the sacrifices that we made on our missions will be of the greatest benefit to us as we learn to apply the lessons that we learned during those 18-to-24-months of service. God has prepared a unique mission experience for each of His children who is willing to dedicate their lives to Him. As we make covenants with our Father in Heaven, He will do all that is in His power to bring us back to return and be with Him again.

This entire talk can be found here: https://www.churchofjesuschrist.org/study/general-conference/2011/10/the-opportunity-of-a-lifetime?lang=eng