167. 1. Imam Ali al-Naqi (p) was asked: What is the minimum necessary knowledge about God?
Imam Ali al-Naqi (p): Affirmation that there is no god but God. Nothing is like Him and He is peerless and eternal, has positive existence, is not nothingness and verily there is nothing like Him.

168. 2. Tahir ibne Hatim al-Qazwini was one of the companions of Imam Ali ar-Reza (p) and had gone astray by becoming a Ghali (extremist) but subsequently reformed his ideas and became firm in his belief.
Tahir asked the Imam (p) in writing: Does the recognition of the Creator remain inadequate and defective?
Imam Ali ar-Reza (p) wrote back: To believe in the fact that He is eternally the All-Knowing, All-Hearing and All-Seeing and that He is fully capable of doing whatever He wants or intends.
Imam Muhammad al-Baqir (p) was also asked the same question by another person to whom he (p) replied: There is nothing like Him and nothing bears any resemblance to Him. He is eternally the All-Knowing.