Matthew 12:39

Evil and adulterous. They were “adulterous” in the sense that they had broken the tie that bound them to God as His chosen people. In the OT, apostasy was commonly spoken of as adultery (see on Ps. 73:27).

Generation. See on chs. 11:16; 23:36.

No sign. A hardened and apostate people had no right to demand a sign, and had it been given they would not have accepted it. There was nothing to be gained by casting “pearls before swine” (see on ch. 7:6). In “Moses and the prophets” (see Luke 16:31) there was sufficient light to guide men into the way of salvation, and accordingly the basic reason why the scribes and Pharisees refused to accept Christ was that they had not really accepted the OT Scriptures that testified of Him (see John 5:45-47).

Jonas. That is, Jonah. In what sense was the prophet Jonah a “sign”? The answer lies in those aspects of Jonah’s ministry on which Christ now comments. The first of these “sign” elements in the experience of Jonah was his encounter with the monster of the deep (v. 40); the second, his successful preaching to the people of Nineveh (v. 41).