Main point summary
Even the Ninevites, a brutal and idolatrous race that tormented Israel, recognized God's judgment coming when Jonah, a simple human prophet, preached to them, and they repented. But Israel's own religious leaders, who are supposed to know and teach God's word, do not recognize their own God, and refuse to repent.
Mt 12 Arc
Then some of the scribes and Pharisees answered him, saying, “Teacher, w we wish to see a sign from you.”
But he answered them, x “An evil and y adulterous generation seeks for a sign,
but no sign will be given to it except the sign of the prophet Jonah .
For z just as Jonah was three days and three nights in the belly of the great fish,
a so will the Son of Man be three days and three nights in the heart of the earth.
b The men of Nineveh will rise up at the judgment with this generation and c condemn it,
for d they repented at the preaching of Jonah,
and behold, e something greater than Jonah is here.
Jesus has already done many miraculous signs, which the Pharisees are conveniently ignoring (perhaps they are implying a specific sign that Jesus has not yet done, but if so, they don't clarify). In any event, their deliberate ignoring, and sometimes willful misinterpreting, of the signs Jesus has already done, combined with their constant attempts to trap Jesus in His words with tricky questions and set-up situations, and their willingness to manipulate the Holy Scriptures and/or ignore inconvenient passages of Scripture, all clearly show their hearts. This is what informs Jesus' answer to them.
אַל־תַּעַן כְּסִיל כְּאִוַּלְתּוֹ פֶּן־תִּשְׁוֶה־לּוֹ גַם־אָתָּה׃ עֲנֵה כְסִיל כְּאִוַּלְתּוֹ פֶּן־יִהְיֶה חָכָם בְּעֵינָיו׃ Proverbs 26:4-5 4 b Answer not a fool according to his folly, lest you be like him yourself. 5 c Answer a fool according to his folly, lest he be d wise in his own eyes. Proverbs 26:4-5 ESV When I first read these verses years ago, I didn't understand them. That is, I didn't understand how to put them together or what the point was. Do you answer a fool or not? As I have gotten older, and seen more, and grown more and, well, encountered more fools, and seen foolishness in myself that I hope that God is rooting out, these proverbs have become oh-so understandable. Dealing with a fool is a no-win situation. They will twist Truth you say, they will twist Truth you don't say (ie: if you choose to remain silent). Dealing with a fool is a highly frustrating, exhausting and discouraging business. It can seem hopeless as well. But truly there is hope in God, because He can do the impossible: opening a fool's eyes. Pray, pray, pray, because God can do it. And in the meantime, ask God for wisdom in how to deal with the fools in your life. What is the connection between my meditation on Proverbs 26 and the arced passage in Matthew 12? Well, Jesus dealt with a lot of fools, exposed a lot of fools, and I want to learn from Him. I also want to learn from the fools he dealt with--not to be like them. As I was studying Matthew 12, the Proverbs popped immediately into my head. Jesus does miracles and the fools either refuse to acknowledge them, or accuse Him of doing them by Satan's power. Then they ask Him for a sign. What should Jesus do? Should he give them (another) sign, as they ask for? Will they not merely twist it as they have done before? Is not their request completely deceitful? Should he refuse to give them a sign? Will they not merely claim that this proves that He has no power and is not who He claims to be? How to answer the fool? In this particular meeting Jesus chooses something somewhere in the middle. He calls them what they are, an evil and adulterous generation, and points them to the sign that will be, a sign that is also a prophecy (He is telling them what will happen when He dies). It is a rebuke with grace, because the one who chooses to listen to what He said, and later sees it happen, recognizes it and accepts it, will receive salvation. He is giving the fools vital information, but like swine with pearls, many of them will not recognize it. When it is fulfilled they will see that something amazing has happened, but will hate it and spend all of their effort trying to hide and twist it, instead of receiving it. Truth is an unwelcome and hateful thing to a fool. Jesus then points to and highlights the extent of evil foolishness present in the religious leaders. Even the Ninevites , that cruel and idolatrous nation that (by Jesus' time) had been destroyed as punishment from God, had, in it's day, recognized Truth--and that when it came from a bitter human prophet who didn't love them and didn't want them to be saved! They repented and received grace. And here the leaders of the Jewish people, those who spent their life studying God's Words, and on whom the responsibility of leading the people to God rested, hated Truth so much that they didn't even recognize their own prophesied messiah, their own God , coming in sacrificial love to save them. The guilt of these leaders, and the reception that they received when they died and faced God...it's terrifying to think about. May God in His mercy keep us from being like them.