And they shall bind the choshen (breastplate) by its rings to the rings of theephod (apron) … so that the choshen shall not budge from the ephod
The choshen and the ephod were two of the eight special garments worn by the Kohen Gadol. The choshen was a breastplate set with twelve precious stones, each inscribed with the name of one of the twelve tribes of Israel. It was worn on the breast, over the heart. The ephod was an “apron-like garment … worn in the back from opposite the heart below the elbows down to the ankles, with a belt that tied in the front.”  Two gold rings sewn on the ephod’s belt lined up with two gold rings sewn to the bottom corners of the choshen; these were bound together with ribbons of blue wool. It is of utmost importance, the Torah stresses, that the two should remain securely fastened at all times that the priestly garments are worn. In fact, the imperative that “the choshen shall not budge from the ephod” is counted as one of the 613 mitzvot of the Torah.
Therein lies a lesson applicable to each and every individual: there is to be no disconnection between the “upper” and “lower” aspects of life, or between its “forward” and “backward” elements. True, the human being consists of both the sensitive heart and the crass, functional foot; true, life is composed of sublimely spiritual moments as well as the banal tending to one’s material needs. But the two must be securely joined at the waist: the upper must permeate the lower; the external must never lose sight of its inner soul and essence.
Based on an address by the Rebbe, Adar 21, 5748 (March 10, 1988)
Adapted from the teachings of the Lubavitcher Rebbe by Yanki Tauber
 Rashi, Exodus 28:6
 Sefer HaSichot 5748, p. 314