Light is the translation of the Hebrew word AUR (pronounced as the English 'ore'), The Greek equivalent is
φῶς (phos, or fos; pronounced fohs). Created by the spoken word of God on the first day of creation, light pierced the darkness of the universe forever putting into motion the time-space continuum. The universe, at the time a mass of incredible size, quickly distributed visible light creating a darkened portion opposite of the presence of God. God called the lit side, Day, while the darkened side was called Night.
It would not be until the fourth day of creation that light bearers, called MAUR (pronounced mah-ore) or "lights" to shine in the heavens. The light of the first three days is most probably best understood in some way to be evidence of the presence of God Himself. On the fourth day, God would make the sun and the moon as local "lights" for the benefit of the new planet perfectly prepared for life: the "Earth" - "erets" in the Hebrew language.
This differentiation between light and darkness would be dramatically used as a lesson to the Egyptians, as a great darkness would envelope everywhere but the part of the land in which the slave population -- the Israelites -- was living. Then, to show His presence to the people as they escaped into the wilderness, Yahweh showed Himself as a huge column of light during the night.
Inside the darkness of the inner sanctuary of the tabernacle, light was provided using lamps burning olive oil. No lamps were constructed for the innermost chamber, where the ark of the covenant was. The only light there was provided directly by God, even as was the case on the first three days of creation.
Throughout the history of the people of God in the Old Testament, light was associated with the dawn, the 'first light' of the morning. Even while the sun was still hidden behind the horizon, light dispelled darkness and made it safe to begin a day's work or journey.
In the antiquity of the story of Job, light is used to indicate both knowledge and life itself. Moving into the poetry of the Psalms, light indicates a safe path and even the presence of God. This motif is seen even more clearly in the prologue of the gospel of John, where the Word -- God made known to the universe -- is both the source of life and of truth. John would even use light as synonymous with God himself.
In the end, there will be no more darkness for the people of God. Not only will they be clothed with light, but God Himself will dwell in the midst of them in such as way that it will always be "Day." Only those outside of God's presence -- by definition "hell" -- will know darkness. Their darkness will be of such a curse that it will torment them for as long as they exist.