"You'll never rise higher in all your lives"

I agree with this

"Behold how great is your calling” (D&C 112:33). How great is your calling! You are not sent here to take pictures. You are not sent here to play. You are sent here to find and teach. That's our opportunity, our challenge, and our responsibility. You'll never rise higher in all your lives than you will do while you are in the mission field. That may sound like a strange thing. I said that once in Argentina many years ago, and about ten years later I received a letter from a young man who said, "When I was on a mission in Argentina, you came there and you put a hex on me. I haven't been able to lift it. I have been no good ever since. I failed in school, I failed in my work, I failed in my marriage." I didn't put a hex on him. I simply told him that he would never stand taller, never rise higher, than while in the service of the Lord, and his subsequent life demonstrated that.

This is the great day of your opportunity to establish within yourselves habits of work that will bless you throughout your lives. Said the Lord, "And if your eye be single to my glory, your whole bodies shall be filled with light, and there shall be no darkness in you." (D&C 88:67.) If you concentrate on the work of the Lord, if you give it everything you have, your whole body shall be filled with light, and there shall be no darkness in you. Gone will be the darkness of sin. Gone will be the darkness of laziness. Gone will be all of these negative things. That's the word of the Lord to you and to me.
(Belgium Brussels Missionary Meeting, June 12, 1996) As quoted in (Gordon B. Hinckley, The Teachings of Gordon B. Hinckley, Salt Lake City: Deseret Book, 1997, p. 362)

And this

If we want to keep the Spirit, we must work.

There is no greater exhilaration or satisfaction than to know, after a hard day of work, that we have done our best.

I have often said that one of the greatest secrets of missionary work is work! If a missionary works, he will get the Spirit; if he gets the Spirit, he will teach by the Spirit; and if he teaches by the Spirit, he will touch the hearts of the people and he will be happy. Work, work, work—there is no satisfactory substitute, especially in missionary work.

We must not give Satan an opportunity to discourage us. Here again, work is the answer. Missionary work brings joy, optimism, and happiness. The Lord has given us a key by which we can overcome discouragement:

“Come unto me, all ye that labour and are heavy laden, and I will give you rest. Take my yoke upon you, and learn of me; for I am meek and lowly in heart; and ye shall find rest unto your souls. For my yoke is easy and my burden is light.” (Matt. 11:28–30; italics added.)

In the Savior’s time, the purpose of a yoke was to get oxen pulling together in a united effort. Our Savior has a great cause to move forward. He has asked all of us to be equally yoked together to move His cause forward. It requires not only a united effort; it requires complete dependence on Him. As He said to His early Apostles, “Without me ye can do nothing.”

Our work will be light and easy to bear if we will depend on the Lord and work.
(Ezra Taft Benson, “Keys to Successful Member-Missionary Work,” Ensign, Sep 1990, 2)