John Gills Exposition of the Bible Commentary - Genesis 1:18
And to rule over the day, and over the night ,.... The one, namely the sun, or greater light, to rule over the day, and the moon and stars, the lesser lights, to rule over the night: this is repeated from Genesis 1:16 to show the certainty of it, and that the proper uses of these lights might be observed, and that a just value might be put upon them, but not carried beyond due bounds: and to divide the light from the darkness ; as the day from the night, which is done by the sun, ... read more
Matthew Henry's Complete Commentary - Genesis 1:14-19
This is the history of the fourth day's work, the creating of the sun, moon, and stars, which are here accounted for, not as they are in themselves and in their own nature, to satisfy the curious, but as they are in relation to this earth, to which they serve as lights; and this is enough to furnish us with matter for praise and thanksgiving. Holy Job mentions this as an instance of the glorious power of God, that by the Spirit he hath garnished the heavens (Job 26:13); and here we have an... read more