"The great task of life is to learn the will of the Lord and then do it."

- Pres. Ezra Taft Benson, President of the Church, "The Great Commandment—Love the Lord," General Conference, Apr 1988
http://www.lds.org/general-conference/1988/04/the-great-commandment-love-the-lord?lang=eng

"It is by the performance of the plain, simple, everyday duties that devolve upon us that we will grow in the spirit of God."

- Heber J. Grant, Teachings of Presidents of the Church: Heber J. Grant, (2011), 22–32
http://www.lds.org/manual/teachings-heber-j-grant/chapter-3?lang=eng

 “Perhaps the most valuable result of all education is the ability to make yourself do the thing you have to do, when it ought to be done, whether you like it or not.”

- Thomas Henry Huxley, in John Bartlett, comp., Familiar Quotations (1968), 725, as quoted in Ensign, Jan 2010, p. 66
http://www.lds.org/ensign/print/2010/01/latter-day-saint-voices?lang=eng&clang=eng

To break this covenant one needs only to do nothing

 “One breaks [his] priesthood covenant by transgressing commandments—but also by leaving undone his duties. Accordingly, to break this covenant one needs only to do nothing.”

- Pres. Spencer W. Kimball, The Teachings of Spencer W. Kimball, ed. Edward L. Kimball (1982), 497. As quoted by Pres. Thomas S. Monson, First Counselor in the First Presidency, "The Sacred Call of Service," Ensign, May 2005, p. 54
http://www.lds.org/ensign/2005/05/the-sacred-call-of-service?lang=eng#footnote3-25905_000_022

"Do something every day that you don't want to do; this is the golden rule for acquiring the habit of doing your duty without pain."

- Mark Twain
http://www.quotationspage.com/quote/2164.html

God will hold you responsible for those you might have saved

“If you do not magnify your calling, God will hold you responsible for those you might have saved, had you done your duty.”

- Pres. John Taylor, as quoted by Pres. Thomas S. Monson, Second Counselor in the First Presidency in “The Call of Duty,” General Conference, Apr 1986

http://www.lds.org/general-conference/1986/04/the-call-of-duty?lang=eng

Those with testimonies do their duty

“When there throbs in the heart of an individual Latter-day Saint a great and vital testimony of the truth of this work, he will be found doing his duty in the Church. He will be found in his sacrament meetings. He will be found in his priesthood meetings. He will be found paying his honest tithes and offerings. He will be doing his home teaching. He will be found in attendance at the temple as frequently as his circumstances will permit. He will have within him a great desire to share the gospel with others. He will be found strengthening and lifting his brethren and sisters. It is conversion that makes the difference.”

- Pres. Gordon B. Hinckley, as quoted in “Missionary Service, Activation, Temple Work Emphasized in Conference Leadership Meetings,” Ensign, May 1984

http://www.lds.org/ensign/1984/05/news-of-the-church/missionary-service-activation-temple-work-emphasized-in-conference-leadership-meetings?lang=eng

Greatest responsibility is family history

“The greatest responsibility in this world that God has laid upon us is to seek after our dead.”

- Joseph Smith, Teachings of Presidents of the Church: Joseph Smith, (2011), 475

http://www.lds.org/manual/teachings-joseph-smith/chapter-41?lang=eng

“Doing one’s duty is a manifestation of one’s faith.”

- Bishop Keith B. McMullin, Second Counselor in the Presiding Bishopric, “Our Path of Duty,” Ensign, May 2010, p. 14

http://www.lds.org/ensign/2010/05/our-path-of-duty?lang=eng

Family history work is fulfilling one's duty

"The person who is working on his or her family history fits the description of one who is fulfilling his or her duty. I know the effort, I know the expense. I know the difficulties through which one may go to uncover one name. I know our Heavenly Father is aware of these efforts. And those for whom we perform sacred ordinances are aware of our efforts. Oftentimes, in a miraculous way, there shall appear before us a clear pathway through a field of turbulence."

—Thomas S. Monson, "The Key of Faith", Ensign, February 1994