Physical gathering of the Saints:
Saints gathered together in Kirtland, Ohio; Missouri; Nauvoo, Illinois; and finally the Great Basin. Then the gathering changed from one central point, to stakes around the entire world: Bruce R. McConkie stated:
The] revealed words speak of … there being congregations of the covenant people of the Lord in every nation, speaking every tongue, and among every people when the Lord comes again. …
“The place of gathering for the Mexican Saints is in Mexico; the place of gathering for the Guatemalan Saints is in Guatemala; the place of gathering for the Brazilian Saints is in Brazil; and so it goes throughout the length and breadth of the whole earth. Japan is for the Japanese; Korea is for the Koreans; Australia is for the Australians; every nation is the gathering place for its own people” (in Conference Report, Mexico and Central America Area Conference 1972, 45).
Now we gather in our own stakes. President Benson taught as we gather in stakes, we have this protection:
1. [Stakes are] to unify and perfect the members who live in [their] boundaries by extending to them the Church programs, the ordinances, and gospel instruction. “2. Members of stakes are to be models, or standards, of righteousness. “3. Stakes are to be a defense. They do this as stake members unify under their local priesthood officers and consecrate themselves to do their duty and keep their covenants. … “4. Stakes are a refuge from the storm to be poured out over the earth” (“Strengthen Thy Stakes,” Ensign, Jan. 1991, 2, 4–5)
Gathering means temple building.
The Saints dedicated land to build temples in three places in Missouri, and built the first latter-day temple in Kirtland, Ohio. The temple in Kirtland was built and Joseph Smith received the keys for the gathering of Isreal. From the very beginning the temple has been integral to the gathering of the Saints. Gathering means to take out of the world and bring into the kingdom. As we become a covenant making and covenant keeping people, the protection of the Lord will be with us, and we become sanctified--thus we are gathered into God's kingdom.
Finally, gathering is a personal choice. As we hear the word of God, hearken to the word of God, and humble ourselves, we will be gathered.
He will gather his people even as a hen gathereth her chickens under her wings, even as many as will hearken to my voice and humble themselves before me, and call upon me in mighty prayer. D&C 29:2