Jesus condemns the scribes and Pharisees as an “evil and adulterous generation” for demanding a sign. Israel is being conceived, clearly, as a faithless bride; and she is a faithless bride because, in the face of countless signs of Yahweh’s favor to Israel in Jesus, she is still searching for some indication of that favor. They are like the generation of the exodus, an “evil generation” (Deuteronomy 1:35).

One of the interesting things about Jesus’ statement is that the generation - a time-slice of Israel - is considered adulterous. That is, it’s not Israel in her whole history, but Israel in a single generation that is the faithless bride. Each generation of the bride has to prove herself faithful; even if the last generation clings to her husband, the next may be adulterous.