Albert Barnes on Revelation 15:6

And the seven angels. Rev 15:1.

Came out of the temple. Were seen to come from the temple; that is, from the immediate presence of God.

Having the seven plagues. Rev 15:1. Each one entrusted with a single "plague" to be executed upon the earth. The meaning here is, that they were designated or appointed to execute those plagues in judgments. The symbols of their office--the golden vials--were given to them afterwards, Rev 15:7.

Clothed in pure and white linen. The emblem of holiness--the common representation in regard to the heavenly inhabitants. Rev 3:4; 7:13. Compare Mt 17:2, Lk 9:29, Mk 16:5.

And having their breasts girded with golden girdles. Rev 1:13. The meaning is, that they were attired in a manner befitting their rank and condition.