"Immediately after the tribulation of those days: The sun will be darkened, and the moon will not shed its light; the stars will fall from the sky, and the celestial powers will be shaken.
References for Matthew 24:29
"Then the sign of the Son of Man will appear in the sky, and then all the peoples of the earth will mourn; and they will see the Son of Man coming on the clouds of heaven with power and great glory.
References for Matthew 24:30
He will send out His angels with a loud trumpet, and they will gather His elect from the four winds, from one end of the sky to the other.