“For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth.” (Matthew 12:40, NIV)

Most of us want a guarantee of something before we’re willing to step forward into whatever that something is.

I’ll take this medicine if it can be shown that it has worked for others. I’ll buy this car if other owners of the same type of car like it. I’ll take this job if they can guarantee that I won’t be laid off in the next year.

We want a promise or even a sign proving to us that someone or something is reliable. And the thing is we’re not that different from those in the first century.

In Matthew 12 Jesus finds himself in conversation (as often happened) with the Pharisees. They wanted something from him because Jesus had been doing some strange things like saying he was Lord of the Sabbath and healing a man overtaken by demons. They wanted a sign from him to show that he was trustworthy in what he was doing and saying. Jesus response is twofold: 1) a wicked and adulterous generation asks for a sign and 2) no sign will be given except the sign of the prophet Jonah.

Why did the people of Jesus’ day ask for a sign? Jesus says because they were an evil and adulterous. They heard and saw what he had been doing and yet they refused to believe—that’s a wicked thing to do. They had turned their backs on God and created a god based on their own system—that’s an adulterous thing to do.

Jesus would not be acquiescing to their request; instead, he said to them that they already have a sign—if they have the eyes to see. They need only look to Jonah for their sign of what was going on right before them.

Jonah, as they would surely remember but maybe not completely believe, was in the belly of a huge fish for several days. Jesus tells them that, like Jonah in the fish, he will be in the heart of the earth. This is their sign.

The sign for the wicked and adulterous generation was to look back to Jonah—remember that story—and then apply it to what was going to happen to Jesus. If they did so they might come up with something like this:

Jonah was swallowed by a huge fish. / Jesus was swallowed by death on the cross.
Jonah was kept in the belly of the fish for several days. / Jesus remained dead and in the grave for several days.
Jonah was spit up on the shore of Nineveh. / Jesus was resurrected from death.
Jonah preached salvation to the Ninevites. / Jesus’ death and resurrection purchased the salvation for his sheep.

The sign they were looking for had already been given to them in the person and work of the prophet Jonah and it would be realized in the person and work of Jesus Christ.