Joel 2:31 predicts, “The sun shall be turned to darkness, and the moon to blood, before the great and awesome day of the LORD comes.” Will the sun literally be turned black and the moon turned to blood?
Not necessarily. As with many descriptive passages in prophecy, this prediction is stated in the language of appearance and should not be taken as a technical statement. The idea is that the sun’s light will be blocked and the moon will have a reddish appearance, like blood.
The sun turning to darkness takes place on occasion during a solar eclipse. It is possible that this natural phenomenon will be a sign of the Lord’s soon coming during the end times. Or it could be a supernatural darkness, similar to the darkness that took place during Jesus’ crucifixion (Matthew 27:45).
For a solar eclipse to take place at a particular time may not seem to be a big deal. There is a total solar eclipse visible somewhere around the globe about every 18 months. However, from any one location on Earth, total eclipses take place on average only once in several hundred years.
It is likely that Joel’s prophecy includes an eclipse visible in Israel just before the second coming of Christ. This would be evidence of God’s intricate timing. However, it is also possible that a supernatural event will occur, blocking the sun’s light from the entire planet. This would explain how the sun could look dark and the moon red at the same time—although the prophecy does not stipulate that the two events are simultaneous.
The moon appears red during a total lunar eclipse. Again, it will be the timing of this event that will reveal God’s supernatural power.
Jesus spoke of this event in Matthew 24:29–30: “Immediately after the tribulation of those days the sun will be darkened, and the moon will not give its light, and the stars will fall from heaven, and the powers of the heavens will be shaken. Then will appear in heaven the sign of the Son of Man, and then all the tribes of the earth will mourn, and they will see the Son of Man coming on the clouds of heaven with power and great glory.” Here, Jesus indicates that these phenomena will take place at the end of the tribulation period shortly before He returns to Earth. It is possible that the judgments and devastation that take place during the tribulation will be responsible for creating conditions that make the sun appear dark and the moon appear red.
Regardless of how it happens, the appearance of the sun and moon will change. Joel’s prophecy is clear: a darkened sun and reddish moon are associated with God’s judgment shortly before the return of Christ.