Fourth Book of Kings (Author Compiled by Isaias and Jeremias from records of Nathan, Gad, Addo, Ahias, Jehu and others.)
1:10respondensque Helias dixit quinquagenario si homo Dei sum descendat ignis e caelo et devoret te et quinquaginta tuos descendit itaque ignis e caelo et devoravit eum et quinquaginta qui erant cum eo
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.