The Shaykh Hammad al-Ansari mentioned the fourth type of tawhid (the oneness of Allah), which is: tawhid al-mutaba'ah (following the Prophet), so how is this explained?

Question:
He says: Honorable Shaykh, may Allah grant you success. Shaykh Hammad al-Ansari (may Allah have mercy on him) mentioned in his book *Masail fi al-'Aqidah* (Issues in Creed), in the interpretation of Surat al-Fatihah, that tawhid has four categories. He mentioned the fourth category, which is tawhid al-mutaba'ah, following the Prophet (peace and blessings be upon him). How is this explained?

Answer:
Yes, some of them mention this. They mention that it is a fourth type, but in reality, it is not part of tawhid; rather, it is part of following and emulating the Messenger (peace and blessings be upon him). It is not called tawhid. Tawhid is singling out Allah (Exalted and Majestic is He) in worship. Is it said that the one who disobeys the Messenger is a mushrik (one who associates partners with Allah)? The one who contradicts tawhid is a mushrik, but the one who contradicts the Messenger is a sinner, not a mushrik? He is a sinner. Yes. So Shaykh Hammad followed what some of them mentioned, but there is a point of concern regarding it. Yes.