Mark 8:12

‘And he sighed deeply in his spirit and says, “Why does this generation seek a sign? Truly I say to you, there shall be no sign given to this generation.”

Their unbelief moved Him deeply, and He recognised that that unbelief was not only in them but in many of the people who had crowded around to see miracles. They were all looking for the wrong thing. And He was greatly distressed by it. After all that He had done and taught, all that they could think of was spectacular signs.

‘This generation.' That is, the majority who failed to truly respond to His words. It included the Pharisees, the Scribes, the people of His own home region (Mark 6:1) and and all who rejected the message of His disciples (Mark 6:11). But no sign would be given them for any such sign would have produced the wrong result. If they had had eyes to see they had in fact seen much that demonstrated that the Kingly Rule of God had drawn near, but it had not convinced them, because it was not what they wanted. They did not want a call to obedience and moral rectitude. They wanted to be lifted along on a wave of divine power and to be given freedom to live as they wanted to live, freedom from the Romans and all their adversaries, so that they could follow their own ways. They wanted a heavenly visitant, revealing what they thought of as heavenly powers, who would do it all for them. They wanted to be miraculously fed by the Messiah, (which interestingly the people of Decapolis had been). These were the signs that their literature had promised them. For the truth was that these great ‘seekers after righteousness' had lost the moral dimension.