[Ali Imran]

“Be not deceived; God is not mocked: for whatsoever a man soweth, that shall he also reap.”
‭‭Galatians‬ ‭6‬:‭7‬ ‭KJV

Would you like to see how the authors of the Gospels kept changing and adding words into Jesus's mouth? 

Jesus said, "No signs shall be given" and then he walked away. About 10 years later, another author decided to change that and wrote that Jesus gave a sign. Which one is the correct one?

This is purely academic, not mocking.