Matthew 12

The sign of the prophet Jonah

38 Then some of the scribes and Pharisees reacted saying, "Teacher, we want to see a sign from you."*Jesus had already performed hundreds of signs, and doubtless they had seen some of them. Their request was not honest. 39 But in answer He said to them: "A malignant and adulterous generation seeks a sign, and no sign will be given to it except the sign of the prophet Jonah. 40 For just as Jonah was three days and three nights in the stomach of the sea monster, so will the Son of the Man be three days and three nights in the heart of the earth.*"In the heart of the earth"—here we seem to have instruction from the Lord on the location of Hades—it is inside the earth, somehow. Compare 1 Samuel 28:13 where Samuel (literally), returning from Hades/Sheol, comes up from inside the earth.