Joseph Smith Jr. said this quote

Happiness is the object and design of our existence; and will be the end thereof, if we pursue the path that leads to it; and this path is virtue, uprightness, faithfulness, holiness, and keeping all the commandments of God.

~ Joseph Smith Jr.

Nothing is so much calculated to lead people to forsake sin as to take them by the hand and to watch over them in tenderness. When persons manifest the least kindness and love to me, O what pow'r it has over my mind.

~ Joseph Smith Jr.

Whatever God requires is right, no matter what it is, although we may not see the reason there of until all of the events transpire.

~ Joseph Smith Jr.

God himself, finding he was in the midst of spirits and glory, because he was more intelligent, saw proper to institute laws whereby the rest could have a privilege to advance like himself. The relationship we have with God places us in a situation to advance in knowledge. He has power to institute laws to instruct the weaker intelligences, that they may be exalted with Himself, so that they might have one glory upon another, and all that knowledge, power, glory, and intelligence, which is requisite in order to save them in the world of spirits. (King Follett Discourse)

~ Joseph Smith Jr.