and the seven angels with the seven plagues emerged from the sanctuary, clothed with clean, bright linen and girded about their breasts with golden girdles.

Revelation 15:5-

Also, they wear golden girdles. Girdles are usually used when a person girds himself for a task to be accomplished. (Leviticus 8:7, 13; 1 Samuel 2:18; Luke 12:37; John 13:4, 5) So the angels are girded for carrying out an assignment. Moreover, their girdles are golden. In the ancient tabernacle, gold was used to represent divine, heavenly things. (Hebrews 9:4, 11, 12) That means that these angels have a precious, divine commission of service to perform.