it would not necessarily follow, if He were everywhere, that one could properly direct one’s supplication to Him toward the earth, behind us, or to our right or left. That follows only if one must be able to point toward Him wherever He is. Indeed, what he said goes beyond merely permitting one to point toward Him: he maintained that pointing and directing one’s supplication toward a direction other than above would necessarily be valid if He were there.
This argument holds only if pointing upward with one’s hands is pointing toward Allah Himself. Otherwise, his opponent could say to him: “In your view, pointing during supplication is not directed toward Him. Accordingly, pointing toward Him would never be necessary; rather, it is done because of something peculiar to the upward direction other than Allah Most High being there. If you agree with me on this, it follows that, if He were everywhere, one should point during supplication in all other directions, such as downward, to the right, and to the left; for, in your view, pointing with one’s hands is not directed toward Him, but is instead on account of something other than Allah peculiar to the upward direction.”
This is among the arguments used by earlier and later scholars alike. Abū Muhammad ʿAbd Allāh ibn Muslim ibn Qutayba said in his book