The Sign of the Prophet Jonah

Matthew 16:1-4; NKJV

1 Then the Pharisees and Sadducees came, and testing Him asked that He would show them a sign from heaven. 

2 He answered and said to them, "When it is evening you say, 'It will be fair weather, for the sky is red';  

3 and in the morning, 'It will be foul weather today, for the sky is red and threatening.' Hypocrites! You know how to discern the face of the sky, but you cannot discern the signs of the times.  

4 A wicked and adulterous generation seeks after a sign, and no sign shall be given to it except the sign of the prophet Jonah." And He left them and departed.

Earlier in Jesus' ministry some of the scribes and Pharisees asked Him for a sign.  He referred to them as an "evil and adulterous generation" at that time, but then proceeded to give them some insight into His death, burial and resurrection.  Later in His ministry, He will not elaborate.

Matthew 12:38-40; NKJV

38 Then some of the scribes and Pharisees answered, saying, "Teacher, we want to see a sign from You."

39 But He answered and said to them, "An evil and adulterous generation seeks after a sign, and no sign will be given to it except the sign of the prophet Jonah.  

40 For as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth.

Learn the lessons of Christ the first time.  When He speaks listen.  Take His word to heart and understand.