Sentence:  And He laid down for him certain conditions : so that , if he kept the command of God , then he would always remain as he was , that is , immortal ; but if he did not , he would become mortal , <WSD>melting</WSD> into earth , whence his frame had been taken '' . 
Meaning of the word marked with <WSD> tags:  reduce or cause to be reduced from a solid to a liquid state, usually by heating