For I will reveal myself from heaven with power and great glory, with all the hosts thereof, and dwell in righteousness with men on earth a thousand years, and the wicked shall not stand. And again, verily, verily, I say unto you, and it hath gone forth in a firm decree, by the will of the Father, that mine apostles, the Twelve which were with me in my ministry at Jerusalem, shall stand at my right hand at the day of my coming in a pillar of fire, being clothed with robes of righteousness, with crowns upon their heads, in glory even as I am, to judge the whole house of Israel, even as many as have loved me and kept my commandments, and none else. For a trump shall sound both long and loud, even as upon Mount Sinai, and all the earth shall quake, and they shall come forth-- yea, even the dead which died in me, to receive a crown of righteousness, and to be clothed upon, even as I am, to be with me, that we may be one. (D&C 29:11-13)
Commenting on the above pericope, Donald and Jay Parry wrote the following on the topic of Latter-day Saint eschatology:
When Jesus appears in the clouds of glory, he will be accompanied by a great number of righteous individuals. Matthew and Luke identified them as “angels” when they wrote, “For the Son of man shall come in the glory of his Father with his angels” (Matt. 16:27; see also Mark 8:38; Luke 9:26). Paul identified those who will accompany Christ as “saints” (1 Thes. 3:13), as does the Old Testament prophet Zechariah (Zech. 14:5). Paul wrote an epistle “to the saints and faithful brethren in Christ which are at Colosse” (Col. 1:2), prophesying, “When Christ who is our life, shall appear, then shall ye also appear with him in glory” (Col. 3:4; see also 1 Thes. 2:19).
Doctrine and Covenants 76 is the clearest in the description of those who shall appear with Christ in the sky at his coming. It speaks of those who “received the testimony of Jesus,” who kept “the commandments” and were “washed and cleansed from all their sins,” who received “the Holy Spirit by the laying on of the hands,” “who overcome by faith and are sealed by the Holy Spirit of promise,” “who are the church of the Firstborn,” and “who are priests and king. . . . And are priests of the Most High, after the order of Melchizedek. . . . These are they whom he shall bring with him, when he shall come in the clouds of heaven to reign on the earth over his people” (D&C 76:51-63).
Paul’s epistle to the Church members of Thessalonica indicates that righteous souls who are on the earth when Jesus comes again will actually ascend into the clouds to meet him in the air as he descends. The apostle wrote: “For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not [precede] them which are asleep. For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord” (1 Thes. 4:15-17). (Donald W. Parry and Jay A. Parry, Understanding the Signs of the Times [Salt Lake City: Deseret Book Company, 1999], 423-24)
Related to much of the above is the topic of the "Rapture"; for the Latter-day Saint understanding of this concept, see, for example: