The promise is in Zechariah 2:8, "He that toucheth you toucheth the apple of His eye"; the prayer is Psalms 17:8 "Keep me as the apple of the eye"; the fulfillment Deuteronomy 32:10, "He kept him as the apple of His eye." A different Hebrew word from tappunch , namely, ishon , "little man," i.e. "pupil" (Greek kore ) of the eye. Called so from the image formed on the retina. The part most precious and most guarded from attack; which feels most acutely the least hurt, and the loss of which is irreparable.