The question comes up occasionally, perhaps because of what is stated in the gospel of Mark: “Heaven and earth shall pass away; but my words shall not pass away. But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father” (Mark 13:31-32; emphasis added). the phrase “neither the Son” is not found in Matthew or Luke. Jesus Christ knows all things; He possesses the fulness of the glory and power of the Father (see Doctrine & Covenants 93:16-17). Surely He knows when He will return. if He did not know the exact day or time of His return in glory when the Olivet prophecy was uttered, then certainly after His Resurrection and glorification He came to know. It is worth noting that the Joseph Smith Translation of this verse omits the disputed phrase.

Sperry Symposium Classics, Brigham Young University, Religious Studies Center, 2004, p. 201.

Jesus Christ came to earth as a mortal being in the meridian of time. He taught the gospel, bestowed divine authority, organized the Church, and suffered and died as an infinite atoning sacrifice for the sins of the world. He stated that He would come again, would return not as the meek and lowly Nazarene but as the Lord of Sabaoth, the Lord of Hosts, the Lord of Armies. Jesus Christ’s Second Coming is thus spoken of as His coming “in glory”-meaning, in His true identity as the God of all creation, the Redeemer and Judge. His Second Coming is described as both great and dreadful-great for those who have been true and faithful and therefore look forward to Jesus Christ’s coming, and dreadful to those who have done despite to the spirit of grace and who therefore hope against hope that He will never return. The Second Coming in glory is in fact “the end of the world,” meaning the end of worldliness, the destruction of the wicked (Joseph Smith-Matthew 1:4, 31). At this coming the wicked will be destroyed, the righteous quickened and caught up to meet Him, and the earth transformed from a fallen telestial orb to a terrestrial, paradisaical sphere. We will live and move about among new heavens and new earths. The Second Coming will initiate the millennial reign.

Sperry Symposium Classics, Religious Studies Center, Brigham Young University, 2004, p. 202.