JMD has the right of it--you'll see many similiarites between cards, especially if you're using standard Rider-Waite images. For example, The Devil and The Hierophant.
What JMD is also refering to with the Hebrew words is the High Priestess' postion on the Kabbalistic Tree of life. In case you're not familiar, in Kabbala there is a tree formed by two yin-yang sides. The qualities on one side are the "severe" qualities, the ones on the other are the "merciful" qualities. The Tarot Majors form pathways that zig-zagging between qualities up and down the sides of this tree. But the HPS' path is situated dead-center between the two.
Both cards are indicative of a kind of balance. The HPS, representing the moon, is both the light and dark sides of the moon, of instinct, creativity, intuition, secret knowledge. It can illuminate, or it can darken.
Meanwhile, Justice is the more straight-forward balance--what's fair, what's right, what's equal. They are alike in trying to remain in the middle, rather than going to the extremes of black/white.