Allah the Exalted says, “Do not bow down to the sun or to the moon; rather bow down to Allah who created them, if it is Him that you worship” (Fussilat 41:37).
This verse dismantles every form of idolatry: do not prostrate to created things. Among the greatest of creatures are the sun and the moon, and the pagans used to worship them—some devoted themselves to the sun and prostrated before it, others to the moon and to the stars. The people of Abraham, for instance, built temples fashioned after the heavenly bodies and venerated them. Hence His words, “Do not bow down to the sun.”
Prostration means placing one’s forehead on the ground in humble submission to the one worshipped; it is the most exalted act of worship. The Messenger of Allah ﷺ said, “The closest a servant comes to his Lord is when he is in prostration.”
Thus, prostrating on the ground is the highest form of devotion, for you set your face—the most honored part of you—upon the earth for Allah’s sake, worshipping Him and humbling yourself before His Majesty. This is true prostration, and it befits none but Allah.
Prostrating to the sun or the moon, however, is bowing to a mere creature that deserves no such honor. Prostration must never be directed to created beings; it is due solely to the Creator of all beings, while the creatures are, after all, just like you.