What does Luke 7:30 mean?

John the Baptist's ministry was extensive. From his post on the Jordan River east of Jerusalem, he preached to the people of Judea and the Jews from Galilee, Decapolis, and Perea who traveled to the temple for the festivals. Decades after Jesus ascended into heaven, Paul met men following the teachings of John who had never heard of the Holy Spirit (Acts 19:1–7). The Pharisees and Sadducees are painfully aware of John the Baptist, as well. When they came to hear John's message, he attacked them, saying, "You brood of vipers! Who warned you to flee from the wrath to come?" (Matthew 3:7). He called them to repent of their sins and change their ways (Matthew 3:8). Unlike the sinners and tax collectors, they refused.

Jesus has finished telling a crowd of the importance of John's mission as the herald to the kingdom of God. John represents a transition: living as an Old Testament prophet in the days before the Holy Spirit will indwell God's followers (Acts 2:1–4). The crowd knows of John, and many were baptized by him (Luke 7:29).

The Pharisees and their lawyers rejected John's message of repentance and his offer of baptism. Repentance is God's will for them so He can forgive them. Even though Jesus recognizes their ability to keep the Mosaic law (Matthew 5:20), they are born into sin. Heeding John's call to follow the Messiah who can save them is God's purpose. Even after watching Jesus' miraculous works (Luke 7:21) which fulfill prophecy about the Messiah (Isaiah 26:19; 29:18–19; 35:5–6; 61:1), they refuse.

In the next verses, Jesus points out the irony. John wore camel-hair clothes and ate locusts and honey (Mark 1:6). As a lifelong Nazirite, he didn't drink alcohol (Luke 1:15). The Pharisees and scribes rejected him for his extreme asceticism (Luke 7:33). Jesus eats and drinks with tax collectors and sinners (Luke 5:27–32). The Pharisees and scribes reject Him for being a glutton and a drunkard (Luke 7:34). They reject the message that they're sinners, and instead look for faults in the messengers who tell them the truth.

Pharisees belonged to a sect of Judaism that valued the extra-biblical Oral Law. They believe that in addition to the law Moses wrote down, God gave specifics as to how that law should be followed. For instance, they had twenty-four chapters just on how to observe the Sabbath. "Lawyers," or "scribes," were experts in the Mosaic and Oral laws. Usually, they're called "scribes," but Luke's Gentile audience is probably more familiar with "lawyer."

This isn't found in Matthew's account, but he does include something similar in Matthew 21:32.