“The three lines of the shin may be interpreted as three general dimensions of a human being: Kesser (will and pleasure), the intellect, and the emotions.
…Kesser is that which exists beyond the intellect—the dimension of the suprarational… The gematria of Kesser is 620 [representing the] 620 rays of light [that] are imparted to the world through the three literal lines—or channels—of the shin. These rays are bestowed on the world through the right line, which is kindness; the left line, which is justice; and the centerline, mercy.
When the shin is representative of the intellectual dimension, the three lines stand for the three intellectual faculties of the Sefiros: the right line being Chochmah, the flash of an idea; the left line being Binah, understanding; and the centerline Daas, application of knowledge.
Finally, there is the dimension of the emotions, or middos. Here the shin’s right line represents Chessed, kindness; the left line represents Gevurah, severity or discipline; and the centerline represents Tiferes, mercy or compassion.”