“Let them [sun and moon] be for lights in the expanse of the heavens to give [emit] light on the earth.”
Over the years, a number of skeptics have pointed to this verse to claim that if the Bible were really the inerrant Word of God, it wouldn’t make such a basic mistake as saying the moon emits light. The moon has not and does not—as far as we know—emit any sort of light. Instead, our rocky satellite simply reflects light from the sun.
To uncover the answer, consider first how earth-centric our discussions are. We say that the sun rises and sets, even though we know that the earth actually revolves around the sun and rotates on its axis. We say that the stars “come out” at night, even though we know they’re always there—just hidden by the brighter sunlight. Our point of reference determines how we discuss what we see.
To us, the moon does give light upon the Earth. The fact that it does so by reflection rather than emission is not relevant to the biblical passage. The Hebrew word used for emit/give light in this verse ('owr) can mean both “to be or become light” and “to be illuminated or become lighted up” (Strong’s 0215).1 To demonstrate this word picture, imagine that someone uses a mirror to reflect light in your eyes. The ultimate source of the light is not the mirror, but the mirror appears bright to you because you’re on the receiving end of the reflection.
Taking this verse out of context can make it seem inaccurate, but when we step back (cf. Genesis 1:14–18), we understand more about the purpose of this passage. Other than providing light, God created the sun and moon to mark the seasons, days, and years, which they do quite well. Notice that the Bible does not provide detailed schematics and charts on how this works, since God gave humans the ability to discover these through observational science. The purpose here is not to explain all the details (though it is factually accurate and not a simplified metaphor for “primitive humans”); the purpose is to give an overview and the reasons why God did what He did. Thus, the description of the moon as giving light is not detailed, but it is quite accurate.
Ultimately, the Bible does not say that the moon emits light. Only that it is to give light upon the Earth—which it does by reflection.2
The real message to take from this passage is that God created two spectacular heavenly bodies that are constant reminders of His amazing power. This verse lets us (earth-centric humans) know exactly what God intended: how the sun and moon came to be and why He created them.