Jesus weeps because Jerusalem has abandoned the protection of God. Because the people have abandoned God’s protection, they will be handed over to their enemies, who “will encircle you and hem you in on all sides” (Lk. 19:43). They think they are good enough, and so trust in their own goodness. Ultimately, it is not God who destroys them. It is the enemies they think they can win against. They trusted in themselves, and paid the price.
Mary, by contrast, is far better than any person in Jerusalem. She is totally sinless, immaculately conceived. Yet today we celebrate how her parents recognized that, however good their child is, she will need the protection of God. Even if they recognized her goodness, they also saw God’s strength—a strength that we need even more than Mary. None of us is strong enough on our own. Life is hard, and our enemies are legion. Whatever parts of ourselves we keep from God will be vulnerable to attack. Nothing less than a full offering of ourselves will suffice.