The Torah commands that the Choshen Mishpat, the breastplate worn by the Kohen Gadol, must be permanently fastened to the Efod by cords of techeles passing through golden rings, so that it remain firmly attached:

“They shall bind the breastplate by its rings to the rings of the efod with a cord of techeles… so that the breastplate shall not be loosened from the efod” (Shemos 28:28).

This mitzvah forbids separating or loosening the Choshen from the Efod. The Choshen contained the twelve precious stones engraved with the names of the tribes of Israel and rested upon the Kohen Gadol’s heart, while the Efod formed the central garment of the High Priest’s service. Their permanent attachment symbolized the unity of the Kohen Gadol’s role — carrying the people of Israel before Hashem with justice and devotion.

Rambam counts this prohibition among the commandments governing the priestly garments and rules that loosening the Choshen from the Efod violates a Torah prohibition. The careful fastening of these garments reflects the precision and permanence required in the avodah of the Mikdash.

Sefer HaChinuch explains that the priestly garments were designed with exact detail in order to elevate the dignity and reverence of the Temple service. The Choshen, known as the Choshen Mishpat, represented justice and Divine judgment, and its attachment to the Efod expressed the integration of leadership and righteousness in the service of Hashem.

The Choshen contained the Urim VeTumim, through which prophetic guidance was sometimes received. The secure attachment of the Choshen symbolized the stability and reliability of Divine judgment conveyed through the Kohen Gadol.

Beyond its technical function, this mitzvah expresses a broader principle of permanence in holiness. Sacred structures and relationships are not casual or temporary; they must be maintained with care and constancy. The Choshen and Efod together formed a unified garment of sanctity, teaching that Divine service requires harmony and completeness.

Rambam

• Sefer HaMitzvos (Lo Ta'aseh 87): Prohibits loosening the Choshen from the Efod.
• Hilchot Klei HaMikdash 9:10–11: The breastplate was bound to the Efod with cords of techeles passing through golden rings so that it would never be separated.
• The permanence of the attachment reflects the precision required in the avodah of the Mikdash.

Sefer HaChinuch

• Mitzvah 99:
• The priestly garments were commanded in exact detail in order to elevate the dignity and beauty of the service.
• The secure fastening of the Choshen reflects the seriousness and stability required in serving Hashem.

Rashi

• On “ולא יזח החשן מעל האפוד” (Shemos 28:28):
• The Choshen must remain fixed in place and not shift from its position upon the Efod.
• The cords of techeles and golden rings ensured the breastplate would remain properly aligned during the avodah.

Ramban

• Ramban (Shemos 28:28):
• The priestly garments reflect spiritual realities and their exact arrangement expresses the order of Divine service.
• The Choshen, bearing the names of the tribes, symbolizes Israel constantly remembered before Hashem.

Talmud

• Zevachim 88b:
• The priestly garments atone for various sins of Israel.
• The Choshen atones for errors in judgment, reflecting its designation as the Choshen Mishpat.

Midrash & Chazal

• Shemos Rabbah 38:8:
• The garments of the Kohen Gadol correspond to spiritual qualities and bring merit to Israel.
• The Choshen represents justice and righteousness before Hashem.
• Midrash Tanchuma (Tetzaveh):
• The Kohen Gadol bore the names of Israel upon his heart, demonstrating his responsibility toward the entire people.

Acharonim & Modern Torah Giants

• Rav Samson Raphael Hirsch (Shemos 28):
• The attachment of the Choshen to the Efod symbolizes that leadership must be bound to justice and responsibility.
• Malbim (Shemos 28):
• The arrangement of the garments reflects harmony and structure in Divine service.

Chassidic & Mussar Classics

• Chassidic teachings explain that the heart represents inner intention while garments represent outward action.
• The Choshen resting upon the heart while attached to the Efod symbolizes harmony between inner devotion and outward service.
• Mussar works emphasize that stability in avodas Hashem requires consistency and steady attachment to Torah and mitzvos.

Contrast with Mitzvah 318 — Wearing the Priestly Garments

• Mitzvah 318 requires the priestly garments to be worn during avodah.
• Mitzvah 320 requires specific garments to remain permanently attached.
• One governs the presence of garments, while the other governs their structure.

Parallel to Mitzvah 319 — Not Tearing the Priestly Garments

• Mitzvah 319 forbids damaging the priestly garments.
• Mitzvah 320 forbids separating parts of the garments.
• Both mitzvos preserve the integrity of the bigdei kehunah.

Parallel to Mitzvah 301 — Building the Sanctuary

• The Mishkan and its vessels were constructed with precise design and permanence.
• The priestly garments likewise required exact construction and maintenance.
• Both mitzvos reflect that holiness requires order and precision.