Allah—exalted be He—also says:

“Say: ‘To whom belongs the earth and all who are in it, if you really know?’ They will say, ‘To Allah.’ Say: ‘Will you not then take heed?’” (Qur’an 23:84–85),

and He says:

“Most of them do not believe in Allah without still associating others with Him.” (Qur’an 12:106).

Ibn ʿAbbās and others explained:

“You ask them, ‘Who created the heavens and the earth?’ and they reply, ‘Allah,’ yet even so they worship others besides Him.”

This acknowledgement is indeed part of the Tawḥīd that is obligatory, but by itself it does not discharge the obligation, nor does it, on its own, rescue a person from the shirk that is the gravest of sins—one that Allah will not forgive. Rather, he must devote his religion purely to Allah, worshipping none but Him, so that every aspect of his devotion is for Allah alone.

The ilāh—the true God—is the One whom hearts adore. His right to divinity necessarily entails every attribute of perfection; therefore none is worthy to be worshipped and loved for his very essence except Him. Any deed not intended for His Face is worthless, and worshipping or loving anyone else inevitably leads to corruption, as the Most High says: “Had there been in them both [the heavens and the earth] gods other than Allah, they would surely have fallen into ruin.” (Qur’an 21:22).

We have discussed this matter in greater detail elsewhere.