Charles Ellicott Commentary Matthew 16:4

"An evil and adulterous generation seeketh after a sign; and there shall no sign be given unto it, but the sign of Jonah. And he left them, and departed." — Matthew 16:4 (ASV)

The sign of the prophet Jonah—See Note on Matthew 12:39. As given by St. Mark, the answer was a more absolute refusal: No sign (i.e., none of the kind that was demanded) shall be given to this generation.