William Burkitt on Mark 13:1

Our blessed Saviour being now ready to depart from the temple; never more, after this, entering into it; and his disciples shewing him with wonder and admiration the magnificent structures and buildings thereof, apprehending that in regard to its invincible strength it could not be destroyed, or that at least, in regard to its incredible magnificence, it was a great pity it should be destroyed; they say to Christ, Master, Behold what buildings are here; Not considering how sin would undermine and blow up the most famous structures. Sin brings cities and kingdoms, as well as particular persons, to their end; not one stone of that magnificent structure, says Christ, shall remain unpulled down: which threatening was exactly fulfilled after Christ's death, when Titus, the Roman emperor, destroyed the city, burnt the temple, and Turnus Rufus, the general of his army, ploughed up the very foundation on which the temple stood: thus was the threatening of God fulfilled, Zion shall be ploughed as a field, and Jerusalem shall become an heap Jer 26:18.

Learn hence, 1. That sin has laid the foundation of ruin in the most flourishing cities and kingdoms. That the threatenings of God are to be feared, and shall be fulfilled, whatever appearing improbabilities there may be to the contrary. It is neither the temple's strength nor beauty that can oppose or withstand God's power.