Leviticus 8:9
And he put the mitre upon his head; also upon the mitre, even upon his forefront, did he put the golden plate, the holy crown; as the LORD commanded Moses. And he put the mitre upon his head; also upon the mitre, even upon his forefront, did he put the golden plate, the holy crown; as the LORD commanded Moses.
The setting is the consecration of Aaron as high priest, when he was vested with the sacred garments belonging to that office. The vesting included placing the mitre upon his head and fastening upon its forefront the golden plate, the holy crown. God Himself had appointed the priesthood to Aaron's family, and by this consecration He honored Aaron. In that office Aaron stood as a representative of Christ and as Israel's mediating high priest.