Why do we wrap the tefillin strap around the middle finger 3 times?
First of all, it is important to note that there are several accepted traditions as to how exactly the tefillin straps should be wrapped around your hand. However, all of them include some form of wrapping the strap 3 times around the middle finger. The symbolism of the 3 is that of the triple-bond of love between G-d and Israel, as referred to in the verse, “A three-ply cord is not quickly broken” (Ecclesiastes 4:12). As such, it is as if we are placing a triple wedding ring on our finger. Significantly, as we wrap the straps around our finger, we say the verses which describe the three-fold “I betroth you to me…” (Hosea 2:21-22).