The Imaam, Aboo Ja’far at-Tahaawee (d.321H) – rahimahullah – said in the introduction of his text concerning ‘aqeedah (belief), commonly-known as, at-Tahaawiyyah, “We say concerning the Tawheed of Allaah, whilst believing in the guidance of Allaah: that Allaah is One without any associate, and there is nothing similar to Him, and nothing can render Him incapable and there is no deity besides Him…”

Refer to al-‘Aqeedatut-Tahaawiyyah (p. 5), with notes of ‘Abdul-‘Azeez Ibn Baaz.

So his statement, ‘Allaah is One without any associate,’ comprises the three categories of Tawheed. So He (Subhaanahu wa Ta’aala) is One without any associate in His Ruboobiyyah, One without any associate in His Uloohiyyah and One without any associate in His Names and Attributes.

And his statement, ‘and there is nothing similar to Him,’ is from Tawheedul-Asmaa’ was-Sifaat.

And his statement, ‘and nothing can render Him incapable,’ is from Tawheedur-Ruboobiyyah.

And his statement, ‘and there is no deity besides Him,’ is from Tawheedul-Uloohiyyah.

So these three categories of Tawheed are clear and elucidative in the text of the Imaam (rahimahullah). Indeed, he has mentioned in his aforementioned text that it encompasses, “an explanation of the ‘aqeedah of Ahlus-Sunnah wal-Jamaa’ah upon the madhhab of the fuqahaa’ (jurists) of the Religion: Abee Haneefah an-Nu’maan Ibn Thaabit al-Koofee (d.150H), Abee Yoosuf Ya’qoob Ibn Ibraaheem al-Ansaaree (d.182H) and Abee ‘Abdullaah Muhammad Ibnul-Hasan ash-Shaybaanee (d.189H) – RadiyAllahu ‘anhum – and what they believed from the foundation of the Religion and what they worshipped the Lord of the worlds with.”

Source: The Beneficial Summary in Clarifying the Evidences for the Categories of Tawheed, The Noble Shaykh, Dr. ‘Abdur-Razzaaq Ibn ‘Abdul-Muhsin al-‘Abbaad, Translations and additions by Maaz Qureshi, Sunnah Publishing, pp.55-56.