I believe that when we determine within our hearts that by and with the blessings of God our Heavenly Father we will accomplish a certain labor, God gives the ability to accomplish that labor; but when we lay down, when we become discouraged, when we look at the top of the mountain and say it is impossible to climb to the summit, while we never make an effort it will never be accomplished.
-Heber J. Grant
Teachings of Presidents of the Church: Heber J. Grant, 37.