YOU SAID:

if the mountain won't come to Muhammad, then Muhammad must go to the mountain

INTO JAPANESE

もし山がムハンマドに来ないなら、ムハンマドは山に行かなければ

BACK INTO ENGLISH

If the mountain does not come to Muhammad, Muhammad must go to the mountain

INTO JAPANESE

山がムハンマドに来なければ、ムハンマドは山に行かなければなりません

BACK INTO ENGLISH

If the mountain does not come to Muhammad, Muhammad must go to the mountain