In Matthew 12, Jesus challenges the Pharisees and their evil words. What is in our hearts comes out in our words and a bad tree produces bad fruit, just as a good tree produces good fruit. The Pharisees asked for a sign. Jesus didn't give them a sign, but rather pointed them to the Word of God. He answered their request by referring them to Jonah. Jonah was in the belly of a whale for 3 nights and when he rose out of the whale, Nineveh had the opportunity to hear the Word of God and repent. Jesus was crucified and rose from that grave the 3rd day giving each and every one of us the opportunity to humbly repent and choose Jesus as Lord of all. Jesus is interested in our hearts above all. What comes out of our mouths is an overflow of what is in our hearts. When we fill our hearts with things from the Lord, like His Word, He transforms us from the inside out.