Mark 8:12
He sighed deeply and said, why does this generation ask for a sign? Truly I tell you, no sign will be given to it — the deep sigh (anastenaxas, the same as in 7:34) is Jesus' emotional response to the demand. The why does this generation ask for a sign does not mean no signs have been given — the ministry is full of signs — but that the signs given are not producing the response the Pharisees' demand assumes is still lacking. Truly I tell you, no sign will be given — the absolute refusal differs from Matthew's parallel (the sign of Jonah is offered). Mark presents the bleakest possible response to the demand for a confirming sign.