Looking at what leads up to this I'm struck by the fact that Jesus is on the way to Jerusalem...i.e, he is on the way to pay the ultimate price -- to die. Chapter 19 is about multiple kinds of blindness: Those who can't see any good in Zaccheus (while this supposedly unclean tax collector "gets" Jesus and impulsively offers restitution). The servant who is so afraid of the master that he wastes his talents rather than investing them. The Pharisees demanding that Jesus stop the natural outpouring at the arrival of the Messiah. He goes on to drive out those who are selling what is "necessary" for restoring relationship with God, completely blind to the fact that in Christ God is reaching out directly to those excluded by the religious system.
I think Jesus is weeping here for God's chosen, who seem completely blind to what God is about. Their pre-conceptions seem far too strong to allow even the evidence of God's action among them to change them.
Do we ever allow our pre-conceptions, our notions of what God "should" be doing (according to us), get in the way of seeing the Spirit working among us?