Family

"Jerusalem, Jerusalem, the city that kills the prophets and stones those who are sent to it! How often have I desired to gather your children together as a hen gathers her brood under her wings, and you were not willing!" (Luke 13:34)
This shows how Jesus knew that though Jerusalem was a major city for the Jews, it still faced quite a few problems.  It is almost like an elaboration on another statement that a prophet is rejected in his own home.
But Jesus is speaking to us.  Imagine, God is in this world, uniting people and gathering them together in a great unity, but we are going after God and making God's job difficult.  We start to reject those that God sends us.  We turn our backs when people point out what we need to work on.  This is a place where we know that we should be listening to others more and helping others out.  We need to be uniting everybody instead of pushing them away.  We must face everybody with love rather than hate; friendship rather than enmity.