D&C 101: 65 – 101
The Wheat and the tares must be separated into clusters of similarity as part of the harvest process which is why we must build Zion or gather to Zion where the wheat will be attracted to gather and allow the tares to band together into enclaves of those who do not desire and would not be comfortable in Zion.
The Lord also says that the church is not to sell the lands (or other goods) that they have purchased for Zion even if they are unable to live on those lands.