The scriptural content for this post is found in Genesis 1:14-19
In the same way that God illuminated the primordial world with light when he declared “Let there be light” in Genesis 1:3 God places the sun and the moon in the sky to mark the times and seasons. God is not at this time creating the sun and the moon. God created the sun and moon in Genesis 1:1 as part of the creation of the heavens and the earth.
Just as light was not originally visible on the primordial world the sun and moon were also not yet visible in the beginning. Here in verses 14-16 God is allowing the sun and the moon to be revealed in the sky so that their form and not just their light can be perceived from an earthly perspective. Most of us have experienced an overcast day when the light of the sun was seen but the form of the sun itself could not be seen. This is how it was before God revealed the form of the sun and the moon in the sky.
Here in day four God allows the sun, the moon and the stars to appear through the canopy of mist that exists above the firmament. Here God is further establishing the influence of light in the earth by having the various sources of light visible in the sky. This revealing of the heavenly bodies immediately preceded the creation of animal life that could discern various seasons and time and would respond to and benefit from the visible sun moon and stars above the earth.
These heavenly bodies would provide directional guidance as well as a sense of time of day month and year in the earth. Light is the essential medium in creation for the flourishing of physical life and also the metaphorical representation of God’s love in action.