From The Gospel of Mark, by Mary Healy, commenting on Mark 13:24-32
Finally, Jesus comes to the climactic event that will occur after the tribulation already mentioned but in those days, that is, in the same period of unparalleled distress that follows the desolating abomination (see vv. 17, 19–20). Using biblical imagery Jesus describes cosmic upheavals: the sun and moon will be darkened, stars will fall, and the heavenly powers will be shaken. In the prophets such heavenly disturbances symbolize the earth-shattering impact of God’s judgment upon a rebellious city or empire. But what do they signify here?
On one level, Jesus is giving a symbolic portrayal of the fall of Jerusalem and the temple. For the Jews the temple was a microcosm of the universe. Images of the stars and constellations were embroidered on the temple veils; the seven lights of the menorah represented the sun, the moon, and the five known planets. The temple was the center of the universe, the meeting point of heaven and earth. Thus its destruction would be a cataclysm of cosmic proportions. In this sense Jesus’ words were fulfilled in AD 70, when the Roman legions under Titus reduced the temple to charred rubble and permanently ended the old covenant sacrifices.
But Mark hints at other levels of meaning. Jesus’ words were also fulfilled in part at his crucifixion, when the sun was darkened at midday (15:33).18 Mark has already suggested that the temple prefigures the mystery of Jesus himself, the new and definitive dwelling place of God among his people (see on 9:7; 12:10–11). Jesus’ bodily death portends the destruction of the earthly temple, bringing the transition from the former age to the new and final age of salvation history.
Ultimately the imagery of heavenly chaos—a kind of undoing of God’s work of creation (see Gen 1:14–18)—points to the end of the world (see 2 Pet 3:10; Rev 21:1). For Mark these various levels of meaning are closely interconnected. The end time tribulations begin in Jesus’ own passion, which signals the end of the age of the old covenant and ultimately the end of the universe that will follow the final upheavals at the close of history.