In Mark 13:20, the Lord Jesus says, “And except that the Lord had shortened those days, no flesh should be saved: but for the elect’s sake, whom He hath chosen, He hath shortened the days.” Does this mean that the Lord will shorten the tribulation period from the prophesied seven years to a shorter time span, or is the seven years the shortened period?
Verse 14 refers to “the abomination of desolation, spoken of by Daniel the prophet, standing where it ought not,” which occurs at the midpoint of the seven-year tribulation period and begins the Great Tribulation, a time when there will “be affliction, such as was not from the beginning of the creation” (v19). These awful sufferings continue until they “see the Son of man coming in the clouds with great power and glory” (v26). During this Great Tribulation, those who are “in Judaea” are to “flee to the mountains” (v14). Revelation 12:6 describes fleeing Israel as a woman who “fled into the wilderness, where she hath a place prepared of God, that they should feed her there a thousand two hundred and threescore days.” This length of time is again given in Revelation 12:14, where “she is nourished for a time, and times, and half a time,” or three and a half years. The same length of time is allotted to the beast in Revelation 13:5 to “speaking great things and blasphemies; and power was given unto him to continue forty and two months” (42 x 30 days = 1260 days). Since the Spirit of God has given us the precise duration of the Great Tribulation (the context of Mark 13:20) in multiple scriptures and in three ways of counting time (in days, in months and in years), it is most unlikely that “He hath shortened the days” contradicts the 1260 days prophesied by reducing the number.
Could the Lord be saying that the length was originally longer, but that He shortened it to 1260 days? It is possible, but I don’t know of other scriptures supporting this idea. On the contrary, the week of years (seven-year period) divided in two periods of three-and-a-half years, is firmly established in Daniel 9:27. The Lord’s designation of 70 weeks, with the last week’s two equal parts, is a cornerstone of the prophetic timetable in Scripture, making it doubtful that the final three-and-a-half-year segment is a now-shortened version of an originally longer period.
A third suggestion better explains Mark 13:20 and Matthew 24:22. “He hath shortened the days” may refer to the length of each actual day. This could be the number of hours of daylight, or even the time for the earth to complete one full rotation on its axis. We know there will be less daylight on earth following the fourth trumpet: “The third part of the sun was smitten … and the day shone not for a third part of it” (Rev 8:12). We also have the precedent of the Lord intervening in the earth’s rotation, giving an extra hour of daylight (Josh 10:12-14). Changes in the earth’s tilt and rotation may also have occurred at the time of the flood and may be implied in Isaiah’s prophecy, “The earth shall reel to and fro like a drunkard” (Isa 24:20). Could it be that in those final years of tribulation the days are shortened to be less than 24 hours each, because if they were the duration they are now, the calamities suffered by humanity would take such a toll that “no flesh should be saved: but for the elect’s sake, whom He hath chosen, He hath shortened the days” (Mark 13:20)?