Exodus 29:6

You are to put the turban on his head and put the holy diadem ¹  on the turban.

Ex 28:36-39; Le 8:9

¹ sn This term does not appear in chap. 28, but it can only refer to the plate with the inscription on it that was tied to the turban. Here it is called a “holy diadem,” a diadem that is distinctly set apart for this service. All the clothing was described as “holy garments,” and so they were all meant to mark the separation of the priests to this holy service. The items of clothing were each intended for different aspects of ministry, and so this step in the consecration was designed to symbolize being set apart for those duties, or, prepared (gifted) to perform the ministry.