Jesus grieves over Jerusalem that has killed prophets and stones those sent to her.
He wanted to father all of them together but they were not willing. He had the heart of a mother hen gathering her chicks under her wings.
They weren't willing.
Consequence: their house is going to be left to the desolate - they will see Him no more- until they say "Blessed is He who comes in the name of The Lord."
I'm no scholar so I could be way off in this interpretation. But before Jesus the Jewish people would go to the temple, to the House of The Lord to see Him.
But the Jewish people as a whole rejected Him. They didn't listen to God when He tried to care for them, they weren't willing to change or so what was right.
So at this point, after Jesus does on the cross, He sends His Spirit to dwell in us and be with us. And this is for all people, not only the Jewish nation anymore. The house of The Lord will be left desolate, and the way they will see Jesus is when they turn and come to Him and welcome the message of those who come in Jesus name.
Like I said, I might be missing things in the big scheme of things in the Bible prophecy, but I know there is truth in this- that God was about to break into the whole world to bring the possibility of relationship with Him. And after He died on the cross these people in Jerusalem were going to have to come to Him and believe that He is their Savior and God in order to be set free.
That is the message of Jesus.