The answer is: Blue

Exo 28:31 - the middle garment, beneath the ephod and above the coat, made from one piece of fabric and similar in design to the robe Christ was wearing at the crucifixon (John 19:23)

The Bible presents the priestly garments as not just clothing but deeply symbolic attire, intricately connected to their spiritual role. When we think of the color blue in the context of the priest's robe, it evokes a celestial connection, hinting at the divine and the sacred. Interestingly, blue has often stood as an emblem of both heaven and purity throughout Scripture. Thus, the blue robe plays an essential role in representing the mediator between God and humans—especially as we consider that these garments were related to ritual practices central to ancient worship.

Let’s also hone in on that striking connection with the crucifixion robe in John 19:23. This link isn't just a trivia point; it brings layers of meaning that suggest continuity between the Old Testament priesthood and the embodiment of its fulfillment in Christ. The traditions intertwine, showing a consistent theme of sacrifice, role, and redemption across generations.

Trivia to chew on: There’s something interesting about the ancient cultures around Israel—all had vibrant color codes for their priests. But blue was pretty special for the Israelites! It was often considered a sacred color in their tapestry of faith. In a world so starkly contrasting this vibrant blue fabric, with its notions of transgressions often veiled, the bright blue of these robes called the faithful back to their core relationship with the deity overseeing all creation. Isn’t it captivating how a simple color can tell such profound stories within the biblical narrative?