http://www.dhikrullah.com/knowledge/...ht-surah-noor/
Imam Ibn ul Qayyim al Jawziyyah
The Invocation of God - Al-Wabil al-Sayyib min al-Kalim al-Tayyib
God strikes a parable about His light within the heart of His servant, which only the learned understand: ‘God is the light of the heavens and the earth. The similitude of His light is a niche in which there is a lamp. The lamp is in a Glass, the Glass, like a glistening star, kindled from a blessed olive tree, neither of the east nor of the west, whose oil well nigh glows though no fire has touched it: light upon light. God guides to His light whom He wills, and God strikes parables for human beings, and God knows all things.’ [Qur’an 24:35]
Ubayy ibn Ka`b said, ‘the similitude of His light [takes place in] the Muslim’s heart.’ [Ibn Kathir, 3:464] This light, which He has placed in the heart, comes from gnosis, love, faith and the remembrance of God. It is the light that He has sent down to His servants, by which He gives them life, and by which they walk among people. Its origin is in their hearts, but then He strengthens and increases it until it appears upon their faces, limbs, bodies, even their clothes and dwellings. People of this nature perceive it, while others deny it. On the Day of Judgement, however, it will come forth by their faith, and hasten before them in the darkness of the Bridge, that they might cross it. They will proceed in proportion to either its strength or its weakness in their hearts during their life in the world.
For one person, it will be like the sun, for another like the moon, the stars or a lamp. For yet another, this light will be only at the tips of his toes; it will shine, then go out [then shine, then go out]. For just as his light had been in this world, so he shall be given when crossing the Bridge. In fact, it is the selfsame light that had appeared to him before. However, just as the hypocrite has no real light in this world, or has only an outward light but none within, so shall he be given [on that Day] an outward light which will vanish in the darkness and be lost.
It is about this light-its abode, its bearer and its fuel-that God has coined the parable of the niche, which is like the breast. In this niche lies a globe made of purest glass, like a glistening planet in whiteness and purity-a similitude for the heart, likened to glass inasmuch as it possesses the qualities of the believer’s heart: clarity, fineness and firmness. By its clarity [the believer] sees truth and direction; by its fineness he acquires kindness and mercy; by its firmness he combats God’s enemies, and stands firm in his resistance to them and upholds the truth.