DEUT201 It is a positive commandment to know the unity of the blessed God, to believe with complete faith that He is one, without any partner or associate as Scripture states, Hear, O Israel: Hashem our God, Hashem is One [this verse]. This is a main principle of our faith; after the first knowledge that there is a God in existence it is necessary to believe with complete faith that He is simply, utterly one in the utmost degree of unity; He is not a physical being; no concepts about a physical being can apply to Him; nothing that can affect a physical being can affect Him; there is none second [like] to Him; and without Him there is no God. We are duty-bound to bear this belief in mind every occasion and moment ...