The difference between the Names of the Maker (al-Bari), Exalted is He, and the names of persons regarding whom speech has occurred—and which are a proof of existence—is that the names of creation are expressions of utterances established for named entities to indicate them.
I shall clarify the status of the Name and the Attribute regarding expression, persons, and the names which creation needs in order to call upon their Creator by them, if God the Exalted wills. Is it not established that if you say [Allah], it is the Name, and if you say [al-Rahman], it is the Attribute; and Allah is al-Rahman, and al-Rahman is Allah? And God, the Exalted, has said: {Say: Call upon Allah or call upon al-Rahman. Whichever you call upon, to Him belong the Most Beautiful Names}1.
Thus, the Maker indicated to us by this statement that [Allah] conveys the meaning of al-Rahman, and al-Rahman conveys the meaning of Allah; this is from the perspective of the expression upon which the world has agreed.
But as for the perspective of the esoteric knowledge2 and the Persons (al-ashkhas), then Allah is Muhammad inwardly, and Muhammad is the Messenger outwardly.