I look at one of my hands, palm up.
I count the bone segments of my fingers. Two joints of the thumb and three joints of each finger, altogether fourteen on either hand. The Hebrew word for hand is yad, yud dalet. The Gematria sum of 10 (yud) plus four (dalet) is fourteen. There is no surprise here that the Hebrew word for hand is yad, fourteen joints.
But, how is a hand, fourteen, incomplete? Only by virtue of how we can raise this number to fifteen. “Shma Yisrael . . .” and one hand covering the eyes. We conclude with the last word echad. We have a higher, complete unity in the number fifteen.
— from my scratch pad of thoughts that keep me awake,
but based on a Holy Sefer