Shaykh al-Islām and an authority for mankind, Abū al-ʿAbbās Ibn Taymiyyah—may Allah be pleased with him—was asked about someone who says, “There is nothing but Allah,” to which another person replied, “Anyone who says this has disbelieved.”
He answered—may Allah be pleased with him:
Praise be to Allah.
The statement “There is nothing but Allah” is ambiguous: it may convey either a sound meaning or a false one. If the speaker means that there is no Creator but Allah, no Lord but Allah, and none but Allah answers those in distress and provides for His servants, then He is the One who gives and withholds, lowers and raises, honours and abases. He alone deserves to be sought for help, relied upon, and sought for protection, and it is to Him that His servants turn for refuge. For none can withhold what He gives, none can give what He withholds, and a wealthy person’s wealth is of no avail before Him. As the Most High says in the opening surah of the Quran:
“You alone we worship, and You alone we ask for help.”
The Most High also says:
“So worship Him and put your trust in Him.”
And He says:
“Say, ‘He is my Lord; there is no deity worthy of worship except Him. In Him I put my trust, and to Him is my return.’”
All these meanings are sound. They express monotheism explicitly, and the Quran teaches them.