Usul al-Kafi
Book 3: The Book of Excellence of Knowledge

Chapter 18
Interpretation of as-Samad

228. 1. Imam Muhammad at-Taqi (p) was asked the meaning of the word Samad (Self-dependent). (Q, 112:2)
The Imam (p): Samad means the Lord to whom one turns for every need, big or small.

229. 2. Imam Muhammad al-Baqir (p) was requested to say something about the Oneness of God.
The Imam (p): Verily God whose names are blessed and who is exalted in the transcendence of His Essence, is the One (the only One). He is unique in Oneness, and He attributed Oneness to Himself when He was alone (nothing is one and unique in the sense in which God is one and unique.) Then He made His unity manifestly known to His creatures (after their creation). Thus God is One, Unique, Self-dependent (as-Samad) and All-Holy. Everything worships Him and turns to Him for its needs and He encompasses all things in His perfect knowledge…