What was the light before the sun in Genesis ch.1? The bible teaches that there was a light for daytime in the first 3 days of creation week and the celestial bodies (sun, moon, and stars) weren’t made until day four. Isaiah 60:19-20 and Rev 21:22-26 say that at the end of the new creation there will be no sun, moon, or stars and that God will light the universe with his glory. So things go back to the way it was before creation day 4 in Genesis 1.
Genesis says there was a separate light that lit the world that existed before the sun for the first 3 days. It seems the same light will replace the celestial bodies from Day 4 in the future according to Rev 21:23-25, and Rev 22:5, which references Isa 60:19.
Rev 21:23 (NLT) “And the city has no need of sun or moon, for the glory of God illuminates the city, and the Lamb is its light. 24 The nations will walk in its light, and the kings of the world will enter the city in all their glory. 25 Its gates will never be closed at the end of the day because there is no night there.”
Some may question how can the first 3 days be defined without the sun? God’s light, in the beginning, could have been an omnipresent light that lit the whole of space or it could have been a point light like the sun that only lit one side of the earth. The Genesis 1 framework is that God started the clock in darkness and 12 hours later turn on the light, then did that three times (each in 24-hour cycles) and then on Day 4, he made a celestial body to “rule” over the day, while other bodies “ruled” over the night for the earth. Planetary rotation isn’t specifically tied to the sun or any star. All bodies in space rotate, so the biblical day from an astronomy point of view is based on the earth’s 24-hour rotation, and not directly tied to the sun. Therefore the existence of light itself has nothing to do with the celestial bodies in space. Anyone can light a match or rub two sticks together to make a fire to produce light. Lightning produces light right here on earth without the help of anything in space. There are even creatures that produce light through chemistry, these creatures like fireflies and various sea creatures are bioluminescent.
The Big bang model requires stars and suns to come before planets, moons, and asteroids, and some believers have interpreted Genesis so that the initial light that the bible refers to in Genesis 1:3 was a star or some celestial body that we see today, but the bible says those were all made on Day 4 so that isn’t compatible with scripture. This causes conflict with a naturalistic understanding of reality and some Christians have modified their beliefs to retrofit the bible into a naturalist view by saying Genesis 1-11, Satan, and sin are just metaphors and not literal. However, this is not a problem for bible believers like Jesus himself and those that follow him, because God’s glory is what lit the universe before Day 4 and will again at the end. If one believes in a supernatural God, then it seems inconsistent to limit his abilities based on what people who reject God’s existence believe.