Exodus 28:29
"And Aaron shall bear the names of the children of Israel in the breastplate of judgment upon his heart, when he goeth in unto the holy place, for a memorial before the LORD continually."
The breastplate of judgment was a very important part of the garments that Aaron, the high priest, wore. On this breastplate was engraved the names of each tribe of the children of Israel. This breastplate was fastened to the high priest so that those names would be placed over his heart. The breastplate was not just fastened over the shoulders, but on the bottom were two rings so that it could be fastened to the ephod that the priests wore so that that it was secure enough to always be close to the heart of the high priest. God wanted that breastplate to be on the heart of the high priest when he went to offer the sacrifice for the judgment of the people.