A. Read 2Ki 20:1-11 for the story. In v.6 God grants the additional 15 years. Now go to 2Ki 20:21 and 2Ki 21:1 . NOTE Manasseh's AGE (12)! At the time of Hezekiah's prayer the king was unmarried and childless . Had he died childless the bloodline of Jesus Christ would have been severed! Understand that the entire Old Testament concerns itself with this subject from Gen 3:15 forward when Satan was notified that Christ was coming.