“An evil
And adulterous generation
Asks for a sign.
But no sign
Will be given to it,
Except the sign of Jonah.’
Then he left them.
He went away.”
γενεὰ πονηρὰ καὶ μοιχαλὶς σημεῖον ἐπιζητεῖ, καὶ σημεῖον οὐ δοθήσεται αὐτῇ εἰ μὴ τὸ σημεῖον Ἰωνᾶ. καὶ καταλιπὼν αὐτοὺς ἀπῆλθεν.
This saying about the evil generation and the sign of Jonah can be found in Mark, chapter 8:12-13, and Luke, chapter 11:29, and earlier in Matthew, chapter 12:38, plus here, but there are slight differences. Jesus said that they were an evil and adulterous generation (γενεὰ πονηρὰ καὶ μοιχαλὶς) because they were asking for a sign (σημεῖον ἐπιζητεῖ). However, no sign would be given to them (καὶ σημεῖον οὐ δοθήσεται αὐτῇ), except the sign of Jonah (εἰ μὴ τὸ σημεῖον Ἰωνᾶ). There was no further explanation as earlier in chapter 8:12-13, but Matthew used exactly the same words as in the earlier saying. Here, he simply went away and left them there (καὶ καταλιπὼν αὐτοὺς ἀπῆλθεν.) to figure things out. Jonah, chapter 1:17, was where the prophet was in the belly of the whale or the sea monster for 3 days and 3 nights. The obvious comparison between the 3 days and the 3 nights in the belly of the fish and Jesus in the tomb was not lost on the early Christians. This was a clear allusion to the death of Jesus in the tomb for 3 days and 3 nights before his resurrection. But there was no attempt to make it clear here.