"You did not recognize the time of your visitation" (Luke 19:44).
In today's Gospel, Jesus weeps over the city of Jerusalem as he prophecies the destruction of Jerusalem in 70 AD. Again and again the Jewish people throughout salvation history have not realized the time of their visitation. Too often they disobeyed God's commands and as a result they were taken away from their homeland in order to be taught a lesson in trust by their merciful Father.
Let us always be vigilant and live every day as it were our last. Then and only then will we be prepared to receive Christ when he comes to visit us.