The verse of light (ayat al nur) in the Quran speaks of a deep parable on God's light:
۞ ٱللَّهُ نُورُ ٱلسَّمَـٰوَٰتِ وَٱلْأَرْضِ ۚ مَثَلُ نُورِهِۦ كَمِشْكَوٰةٍۢ فِيهَا مِصْبَاحٌ ۖ ٱلْمِصْبَاحُ فِى زُجَاجَةٍ ۖ ٱلزُّجَاجَةُ كَأَنَّهَا كَوْكَبٌۭ دُرِّىٌّۭ يُوقَدُ مِن شَجَرَةٍۢ مُّبَـٰرَكَةٍۢ زَيْتُونَةٍۢ لَّا شَرْقِيَّةٍۢ وَلَا غَرْبِيَّةٍۢ يَكَادُ زَيْتُهَا يُضِىٓءُ وَلَوْ لَمْ تَمْسَسْهُ نَارٌۭ ۚ نُّورٌ عَلَىٰ نُورٍۢ ۗ يَهْدِى ٱللَّهُ لِنُورِهِۦ مَن يَشَآءُ ۚ وَيَضْرِبُ ٱللَّهُ ٱلْأَمْثَـٰلَ لِلنَّاسِ ۗ وَٱللَّهُ بِكُلِّ شَىْءٍ عَلِيمٌۭ
"God is the Light of the heavens and the earth. The similitude of His light is as a niche wherein is a lamp. The lamp is in a glass. The glass is as it were a shining star. (This lamp is) kindled from a blessed tree, an olive neither of the East nor of the West, whose oil would almost glow forth (of itself) though no fire touched it. Light upon light. God guideth unto His light whom He will. And God speaketh to mankind in allegories, for God is Knower of all things."
— M. Pickthall (Quran 24:35)
It is counted among the very striking verses in the scripture, though the Quran is such in its entirely. To understand it better, I benefitted from Allama Tabatabai (d. 1981)'s Tafsir al Mizan, a renowned forty volume exegesis of the Quran. The explanation below is primarily from what I learned there.
So, there are two kinds of light: the universal light (of existence) and the special light (of guidance).
- The Universal Light (of Existence)
The verse speaks of the universal light as "Allah is the Light of the heavens and the earth" meaning that all things appear in the realm of existence by it, and without it, everything would be non existent. The heavens and the earth are lit by this light.
A light is defined as being manifest by virtue of its essence such that it is manifest itself, and it also brings other things to manifestation. God is called Light (Nur). By His illumination, the entire world of creation comes to manifestation.
In the case of divine light, making things appear is the same as making them exist. In the case of physical light however, the manifestation of dark objects is not the same as their existence, since they would exist whether they are shined upon or not.
Existence is the perfect example of light, while contingent beings exist by God’s existentiation (ijad) of them, meaning they exist by His bestowal of existence upon them. Therefore, He is the most perfect instance of light. The existents other than God have borrowed existence/light temporarily from God.
- The Special Light (of Guidance)
The verse speaks of the special light as "The similitude of His light" meaning that it benefits the believers in particular as the light of ma'rifah (gnosis, knowledge of God) and as the light of iman (faith, belief) which will lead to eternal bliss and by it, they will witness what was hidden from them in this world.
God compared this light to a lamp that is in a glass in a niche, kindled by an oil that is at the utmost degree of clarity. The glass also shines as if it were a glittering star, adding light upon light. This lamp is placed in houses of worship where God is glorified by certain believers who are not distracted from the remembrance of their Lord and His service by any trade or sale.
So, there is the distinction made between believers and disbelievers. Believers perform righteous deeds, which leads them to a light from God that results in their knowledge of God, leading to the best rewards and grace to come. Disbelievers perform bad deeds, which leads them to a mirage with no reality, so they are in layers of darkness one above another. They are not given a light from God, so they have no light.
As a possessive ascription, the meaning of "His light" is “the light that belongs to God.” It is not description of God as the light, but is a description of a light that is His, which He shines and bestows upon others. If the analogy was for God’s universal light, it would not be restricted to a certain group, but because the end of the analogy says “God guides to His light whom He wills” (24:35), it can be inferred that this is a description of God’s special light for the true believers.
Therefore, “Allah is the light of the heavens and the earth” means that God is the source of existence for all beings, while “His light” in the subsequent part of the verse refers to His guidance of the believers in particular.
The meaning is that “The light of the lamp is a great light upon another great light.” It has been said that “light upon light” does not imply multiplicity of light, but implies its intensity and strength. That is a quite plausible meaning. Another subtle and elegant interpretation is that the expression could be that the light primarily and in reality belongs to the lamp, but it can also be attributed to the glass, metaphorically. So, there will be two lights based on the two ascriptions though in reality the light is only of the lamp.
The same two perspectives apply to what is being compared. The light of faith and gnosis illuminates the hearts of the believers, which is borrowed light taken from God’s light. What is being compared is God’s light that shines upon the hearts of the believers, like a light that shines from a glass, which is placed on a lamp in a niche that is fueled by a pure and virgin olive oil. The light of this lamp glows from the glass and the nice and is directed at its seekers, centered in the niche and then illuminates the entire house.
Terms
The terms in the verse give imagery of a deeply spiritual and abstract truth which are important to define with more clarity:
Nur (Light): God’s light is compared to the entire image which is depicted by the rest of the verse. It is not compared only to the niche.
Mathal (Example/Similitude/Parable/Likeness/Allegory)
Mishkah (Niche): al Raghib and others have said that a mishkah (niche) is an enclosed hole or opening made in a wall to place certain articles in it, like lamps and other things.
Misbah (Lamp): The placement of glass around the lamp makes the flames of the lamp steadier because it is no longer disturbed by turbulence in its surrounding air such as the flow of wind.
Zujajah (Glass/Crystal): The glass is like a bright shining star, in the sense that it intensifies the light that shines from the lamp.
Kawkab Durra (Shining Star/Brilliant Star): A durri star is a large star that has a lot of light. There are only a few of them in the sky. Iqad means to 'enkindle/inflame/ignite.'
Shajaratin Mubarakatin Zaytunatin (Blessed Olive Tree): The lamp is ablaze and its blaze is from a blessed olive tree, meaning the lamp is kindled by the olive oil that is extracted from such a tree, where oil is implied.
Zayt (Oil): It means ‘olive oil.’ Not being eastern or western means the tree is positioned on neither the west side nor the east side of a hill, such that it would only receive light for half of the day and be under shadow in the other half, which would prevent its fruit from fully growing, and as a result, its oil would not be pure. It would not provide bright, suitable and steady light. In reality, this tree receives sunlight for the whole day which is why its fruit ripens fully and the oil extracted from it will be perfect.
Conclusion
The above analogy implies the underlying secrets of knowledge and deep realities. This transcendent knowledge is expressed by a parable in a way that the subtleties can be available to the learned and unlearned at their particular stations of insight.
God pleases to guide someone only if the person proves to have the capacity for receiving guidance by having good character and practice. This will qualify you to become a recipient of God's special light, in addition to the universal light that all of the cosmos and forms of life are subsisted by.
References
Tafsir al Mizan by Allama Tabatabai - Volume 29 on Surah Nur (Chapter of Light)
Quran English and Arabic - At the timestamp 23:10 is The Verse of Light
