“A wicked and adulterous generation seeketh after a sign; and there shall no sign be given unto it, but the sign of the prophet Jonah. And he left them, and departed.” Matthew 16:4. For as Jonah was a sign unto the Ninevites, so shall also the Son of man be to this generation.” Luke 11:30.
Can you give me an explanation of what exactly is the Sign of Jonah?
Jesus explained this in more detail in Matt. 12:38-42. Even after documented evidence of countless miracles, some Pharisees asked Jesus for a miraculous sign to prove He was who He claimed to be.
The sign of Jonah meant that He would spend three days and three nights in the tomb to support His claim, just as Jonah had spent that amount of time in the whale. The tragedy of this was that because of their unbelief, the religious leaders would only know for sure that Jesus was their long awaited Messiah after they had put Him to death. And although the Lord tarried on Earth for 40 days after fulfilling His promise of the sign of Jonah, they still refused to accept it.