“A wicked and adulterous generation looks for a sign, but none will be given it except the sign of Jonah.” Jesus then left them and went away.” Matthew 16:4
In Matthew 16, The Lord Jesus refuses a sign to the Pharisees and Sadducees because of their wickedness by telling them that the only sign they will have is that of Jonah.
Jonah had been sent to the inhabitants of the city of Nineveh because of their wickedness to announce the destruction of their city. At the announcement of Jonah, the inhabitants of Nineveh proclaimed a fast and repented; Therefore God decided to no longer destroy the city. By referring to Jonah, The Lord Jesus invites the Pharisees and Sadducees to repent, to turn away from their evil ways as did the inhabitants of Nineveh, in order to avoid their destruction, in this case eternal fire.
This refusal of a sign from The Lord Jesus is still applicable to us today. Very often, people are seeking signs from Heaven, they want to obtain blessings while they are not living a life in accordance with God’s Commandments. Even today, The Lord Jesus tells them that no sign will be given to them except that of Jonah. The Lord Jesus invites them to repent.