Jamieson, Fausset and Brown on Genesis 1:16

16. two great lights--In consequence of the day being reckoned as commencing at sunset--the moon, which would be seen first in the horizon, would appear "a great light," compared with the little twinkling stars; while its pale benign radiance would be eclipsed by the dazzling splendor of the sun; when his resplendent orb rose in the morning and gradually attained its meridian blaze of glory, it would appear "the greater light" that ruled the day. Both these lights may be said to be "made" on the fourth day--not created, indeed, for it is a different word that is here used, but constituted, appointed to the important and necessary office of serving as luminaries to the world, and regulating by their motions and their influence the progress and divisions of time.