3Ne Ch21

This chapter is one to really pay attention to because it is directed straight to us of this day. First, Israel will be gathered when the Book of Mormon does and there will be a free people in America (done and done), and also they will be saved if they believe and obey or be cut off and destroyed. Something that hasn't happened yet, I think, is that a New Jerusalem will be build and the lost tribes shall return.
Christ tells the Nephites of a sign that will show when the house of Israel will be gathered again which is that the words that are written to the Gentiles so they will know concerning the remnant of the house of Jacob is written, the work has started (v1-3). Our Father has set up a way for this to happen by freeing the Gentiles in America so they can have the chance to accept the words of God and soften their hearts to be converted and numbered among His people (v4-6). These things have already happened, so the Father's work is already started and is rapidly growing and it is God's marvelous work being spread to everyone by blessed servants of the Lord (v7-10).
As this work proceeds, there will be some that do not accept Jesus Christ, and they will be cut off and destroyed from the covenant that was made to protect followers of the Savior (v11-17). There will be a time when all sins shall be done away with and the ones that were wicked will be plucked from the midst of happiness and have vengeance executed upon them (v18-21). On the other hand, the righteous will be established into a church and numbered among the blessed house of Jacob to assist His work in gathering Israel to a New Jerusalem where Christ will dwell with the people (v22-25). The Father's work will commence and there will be ways to reach all of God's children with His message of love, hope, and gathering to join Christ for a heavenly reward (v27-29).