Quote from President Monson:

"None of us will honor our Heavenly Father and our Savior more than by serving as a devoted, compassionate missionary. Missionary work is hard work. Missionary service is demanding and requires long hours of study and preparation that the missionary himself/herself might match the divine message he proclaims. It is a labor of love but also of sacrifice and devotion to duty. Some of you may be shy by nature or consider yourselves inadequate to respond affirmatively to the call to serve. Remember that this is the Lord's work, and when we are on the Lord's errand, we are entitled to the Lord's help."