Tafsir of Al-Ahzab 33:3

(And rely upon Allah) meaning: entrust all your affairs to Him, the Almighty and Majestic. (And sufficient is Allah as Disposer of affairs) as a Guardian to whom all matters are entrusted. The [explicit] mention of the Divine Name in the place of a pronoun is for the sake of glorification, and so that the sentence may stand independently, like a proverb.