The lights of the sun, moon and stars so that their light is regularly visible from the surface of the earth. In this way the narrative shifts from the very precise word for 'created' to the more general 'made', and then the much broader use of 'set'.
The sun, moon and stars where already created on the fourth day, they were just made regularly visible from the surface of the earth.
Day 1: God 'lets' the light in, thus creating the first day (
Gen. 1:4).
Day 2: God creates the upper atmosphere, called the 'firmament' (
Gen. 1:7).
Day 3: God separates the land from the seas and creates plant life (
Gen. 1:10).
Day 4: God then, 'sets', the heavenly lights in the visible sky (
Gen. 1:17).
Day 5: God creates the birds of the air and marine life (
Gen. 1:21).
Day 6: Finally, God creates the beasts of the field and Man (
Gen. 1:25).
For the first three days of creation does it make any sense at all that they earth was alone in the universe? Or does it make more sense that God was continuing to clear the clouds and altering the atmosphere (firmament), as an ongoing work of creation?
God set the lights in the sky, it does not say God created them on the fourth day.