If joy and peace and rewards were instantaneously given the doer of good, there would be no evil-all would do good but not because of the rightness of doing good. There would be no test of strength, no development of character, no growth of powers, no free agency, only satanic controls.
The Teachings of Spencer W. Kimball, Twelfth President of the Church of Jesus Christ of Latter-day Saints (ed. 1982)