ושמתי כדכד שמשותיך...וכל בניך למודי ה’ ורב שלום בניך.

I shall set your ramparts with kadkod stones…All of your children will be students of Hashem, and your children’s peace will be abundant.[1]

The Gemara presents a homiletical interpretation of the word “כדכד” in the first verse. It refers to a dispute among the Sages as to whether the stones of the ramparts will be shoham (onyx) or yashfeh (jasper). Anticipating this dispute, the verse states that they will be “כדכד,” which is understood as a contraction of the words “כדין וכדין — like this one and like that one,” i.e., the ramparts will be made of both types of stone.[2]

What is the meaning of these two opinions, and of their ultimate unification?

The Meshech Chochmah refers us to the Gemara elsewhere[3] that states that the priestly garments worn by the Kohen Gadol effect atonement for different sins. Within that discussion, it states that the eifod (apron) atones for idolatry, and the choshen (breastplate) atones for perversion of justice. These two garments are represented by the shoham and yashfeh stones:

1. The eifod has two shoham stones that rest on the shoulders.
2. The yashfeh is the final stone on the choshen.

It emerges that these two stones reflect the two domains of correct beliefs and understanding on the one hand, and honesty and justice in interpersonal dealings on the other. As such, the discussion as to what the future ramparts of Jerusalem will be made from reflects the question as to which of these two areas will be perfected in the future. To this, the verse responds, “Like this one and like that one!” For the future Jerusalem will herald perfection in both these areas. This inclusion of both ideas is then detailed in the verse that follows: “And all your children will be students of Hashem” — representing the area of true beliefs and understanding; “And your children’s peace will be abundant” — representing the domain between man and his fellow man, where peace and honesty will reign.

We look forward to the time when we will see the glow emanate from both of those stones and illuminate the entire world.

[1] Yeshayahu 54:12–13.

[2] Bava Basra 75a.

[3] Zevachim 88b.