v1-12 - Jesus addresses the crowd regarding the hypocritical behavior of the establishment (Pharisees, Sadducees & religious scholars).
v13-33 - Jesus uncorks seven "Woes," which doesn't seem to pack much punch in our world. But the way Jesus uses this word in this particular context, it's almost as if He's saying 'To hell with you...' In fact, this section ends in v33 with Jesus saying, "You snakes! You brood of vipers! How will you escape being condemned to hell?"
v34-36 - Jesus speaks of those He will send out in His name: the coming Church. Yet He also indicates that the establishment will persecute and kill them in the same way earlier generations had killed the prophets for saying things nobody wanted to hear, even though the prophets were carrying God's Word.
v37-39 - Jesus tells of His love for His people, even though generation after generation has rejected Him. Now Jerusalem's time as being the particular place where God's presence resides is up, and His presence will not come again until Christ returns victorious, and even those who've ardently rejected Him will be forced to bend their knee before Him.
You're likely reading this on a Monday. You've finally found a few minutes of peace and quiet to read the Bible, hoping to hear words of mercy and encouragement from your Savior, but instead you read about Jesus unloading on the Pharisees with some brutal words. What's going on here???
Remember the context: Jesus has entered into Jerusalem a few days before His death, and the establishment has been been badgering Him with 'gotcha' questions trying to frame Him so they can have Him executed. Jesus has successfully navigated around each challenge, and He's had enough.
Also remember who Jesus is: Certainly a man, but also fully divine. Jesus judgmentally uses very harsh language in cutting the establishment down, but He has the authority to do so. Most of the time (there are exceptions), we don't have any business talking this way about others.
It's good for us to see Jesus in this light. Certainly He is our loving Savior, gently calling children to Him in a way that a shepherd tenderly calls out to His lambs. But Jesus is also Almighty God, a