سورة النساء

Imam Sadiq (peace be upon him): الْبُرْهَانُ [the proof] is Muhammad (peace be upon him and his family), and النُّورُ [the light] is Ali (peace be upon him).

Ali ibn Ibrahim (may Allah have mercy on him): وَ أَنْزَلْنا إِلَیْکُمْ نُوراً مُبِیناً [and We have sent down to you a clear light] — the نُوراً [light] is the imamah of Ali (peace be upon him).

Imam Ali (peace be upon him): Allah has said in Surah al-Baqarah: "Allah is the guardian of those who believe; He brings them out of the darknesses into the light" (Baqarah/257), meaning from the darkness of disbelief to the light of faith — so here faith has been called light. Like where He said in Surah Ibrahim (peace be upon him): "so that you may bring the people out of the darknesses [of polytheism, oppression and ignorance] into the light (of faith, justice and awareness)" (Ibrahim/1). And in Surah al-Tawbah He said: "They desire to put out the light of Allah with their mouths" (Tawbah/32), meaning to cover the light of Islam with their disbelief and rebellion. And in Surah al-Nisa He said: "Allah guides to His light whom He wills" (Nur/35). And in Surah al-Hadid, in describing the qualities of the believers, He said: "their light runs before them and on their right hand [and it is said to them]: good news for you today — gardens beneath [the trees of] which rivers flow" (Hadid/12). "Look at us so that we may take a ray from your light!" (Hadid/13), meaning: by your light we tread our path. There are many similar cases in the Qur'an.