See also: D&C 136:41
We are gathered together expressly to build up the kingdom of God. . . . The voice of God has not called us together from the uttermost parts of the earth to build up and enrich those who are diametrically opposed to His kingdom . . . . No, we are gathered together to become of one heart and of one mind in all our operations and endeavors. — Brigham Young, Journal of Discourses, 12:153
Ephraim has become mixed with all the nations of the earth, and it is Ephraim that is gathering together. . . .
We are gathering the people as fast as we can. We are gathering them to make Saints of them and of ourselves. — Discourses of Brigham Young, 121
We must watch and pray, and look well to our walk and conversation, and live near to our God, that the love of this world may not choke the precious seed of truth, and feel ready, if necessary, to offer up all things, even life itself, for the Kingdom of Heaven’s sake. — Brigham Young, Journal of Discourses, 11-111
God has commenced to set up his kingdom on the earth, and all hell and its devils are moving against it. Hell is yawning and sending forth its devils and their imps. What for? To destroy the kingdom of God from the earth. But they cannot do it. — Brigham Young, Journal of Discourses, 5:74, 75
The Kingdom we are talking about, preaching about and trying to build up is the Kingdom of God on the earth, not in the starry heavens, nor in the sun. We are trying to establish the Kingdom of God on the earth to which really and properly everything that pertains to men – their feelings, their faith, their affections, their desires, and every act of their lives – belong, that they may be ruled by it spiritually and temporally. — Brigham Young, Journal of Discourses, 10:328