Once the King Akbar heard that a certain astrologer was boasting for his accurate predictions. He called him for a test. When he came to the Court, he asked him, "I have heard that you predict very accurately." The astrologer was trembling with fear. "Tell me, when will you die?"
The astrologer said he will have to consult his charts to predict it correctly. The King gave him one hour time to do so. Instead of consulting his charts, the astrologer went to Birbal and described the whole thing. Birbal gave him advice as what he should say to the King.
The astrologer returned to the Court and told the king, "He would die three days before the King." Akbar understood very well that he was bluffing, but he did not want to take any chance, so he let him go. Thus Birbal  saved the astrologer's life.