We are mostly rooted in the final Hey of Hashem's name. While we contain all of the G-dly attributes, being that it is expressed to us through G-d's speech, therefore we are most closely connected to the final Hey. While all of creation emanates from the words of Hashem, a more external form of speech, however, the soul of a Jew emanates from the breath of Hashem. While words can permeate a partition, breath can not. The only separation that impacts the integral Jew-G-d connection is sin.