Jesus had just finished telling off the Scribes and Pharisees for their pious lie that they would not have abused the prophets God had sent to Israel in the past. He pointed out that, if anything, they were worse.
So He promised and prophesied that He would send prophets, sages and men to write Scripture. In saying so, He was indicating He was the Messiah, the Son of God. Like their ancestors, the rabbis would surely kill and crucify them, just as they would the Messiah. His ambassadors would be whipped and chased from town to town, wherever Jews had synagogues.
In this way, the current nation of Israel would exhaust the patience of God under the Covenant of Moses. This would all be part of their final rejection of that covenant. In the record of Israel’s history, they would distinguish themselves by far as the most obstreperous generation of all, spilling more innocent blood than ever before. Jesus cites the long sad history from the murder of Abel just outside the Garden of Eden, all the way to the murder of Zechariah the priest around 800 BC. The latter event was a time when several prophets, including Joel, came to warn King Joash over his allowing the kingdom to slip into idolatry. Zechariah was stoned to death while preaching during a Sabbath worship service in the Temple.
Jesus told them that their response to His message was no less murderous, the kind of in-your-face defiance and provocation of God that would justify the nation’s doom. They would bear the guilt of all their ancestral sins, as well.
We can envision Jesus now turning to face the Temple and crying out. This is the single most recognizable landmark as you approached Jerusalem from any direction. It stood as the symbol of everything that gave the Jewish nation their identity. This is the city that slaughtered the messengers of God. Several times Jesus tried to establish Himself as the Savior, the One who would bring life and redemption to future generations. However, it was the current leadership begging damnation on themselves and all their descendants.
So God would grant their demand. Their dominion and authority under the Covenant would be vacated; their fine Temple and city would be turned into a wasteland. The place would be a burned ruin, symbolizing that the entire future of the nation was forfeited.
Most people miss the point of this last verse here. Jesus hearkens back to the Triumphal Entry a few days before. There, the folks who believed in the symbolism of His actions that day shouted out, quoting Psalm 118. That was a Messianic processional psalm, conjuring the image of the Messiah entering His capitol city to sit on His throne. Once the Covenant was vacated at the Cross, there was only one way Jews could ever restore themselves to God’s favor. They would have to turn to Jesus and declare Him Messiah, just the same as that crowd who welcomed Him with palm branches and clothing under the hooves of the donkey He rode.