The Arabic word illa is a negative word corresponding to the English , and but.
It is an often recurring phrase in the Qur'an, often used to give strength to statements by first negating all possibilities, and then referring to a subject. For example, in the Islamic Creed ():
This can also be seen in the prayer La hawla wa la quwwata <big>illa</big> billah, There is neither change nor power <big>except</big> by means of God.