The scriptures speak of the Master returning as a “thief in the night” (1 Thessalonians 5:2). It is true that no mortal man has known, does now know, or will yet know the precise day of the Lord’s second advent. That is true for prophets and Apostles as well as the rank and file of society and the Church. The Lord did not reveal to Joseph Smith the precise day and time of His coming (Doctrine and Covenants 130:14-17).

Elder M. Russell Ballard, speaking to students at Brigham Young University, observed:

“I am called as one of the Apostles to be a special witness of Christ in these exciting, trying times, and I do not now when He is going to come again. As far as I know, none of my brethren in the Council of the Twelve or even in the First Presidency knows. And I would humbly suggest to you, my young brothers and sisters, that if we do not know, then nobody knows, no matter how compelling their arguments or how reasonable their calculations. I believe when the Lord says ‘no man’ knows, it really means that no man knows. You should be extremely wary of anyone who claims to be an exception to divine decree.”

On the other hand, [Mormons] are promised that if they are in tune with the Spirit, they can know the time and the season. The Apostle Paul chose the descriptive analogy of a pregnant woman about to deliver. She may not know the exact day or hour when the birth is to take place, but one thing she knows for sure: it will be soon. It must be soon! The impressions and feelings and signs within her own body so testify. in that day, surely the Saints of the most High, the members of the body of Jesus Christ, will be pleading for the Lord to deliver the travailing earth, to bring an end to corruption and degradation, to introduce an era of peace and righteousness. And those who give heed to the words of scripture, and especially to the living oracles, will stand as the “children of light, and the children of the day,” those who “are not of the night, nor of darkness” (1 Thessalonians 5:2-5). In a modern revelation the Savior declared: “And again, verily I say unto you, the coming of the Lord draweth nigh and it overtaketh the world as a thief in the night–therefore, gird up your loins, that you many be the children of light and that day shall not overtake you as a thief” (Doctrine and Covenants 106:4-5; emphasis added).

Sperry Symposium Classics, Religious Studies Center, Brigham Young University, p. 204.