(Isa. 13:3)
Jehovah’s sanctified ones (Josh. 3:5) are those who are temple worthy, who actually attend the temple, and who are made holy by Christ’s power. In ancient Israel the soldiers prepared for the holy war by participating in holy rituals connected with the temple (Deut. 23:10–15). In this dispensation, Jesus Christ’s soldiers (members of the Church) prepare for the battle against Babylon by participating in temple rituals.
(Donald W. Parry, Jay A. Parry, and Tina M. Peterson Understanding Isaiah, [Salt Lake City: Deseret Book Co., 1998], 131.)
The “sanctified ones” are those whom God will bless. In ancient times these were Cyrus and his Medes and Persians, who were blessed in putting down the wickedness of Babylon. In the latter days it will be the leaders of the gathering hosts of Israel.
“For mine anger IS NOT UPON them that rejoice in my highness” (2 Ne. 23:3; emphasis added). This is a great compliment to Cyrus because he was reared among pagans and never did hear the full message of the Gospel. Nevertheless, the Lord assures him that he will be blessed because he, in his limited way, honored God.
(W. Cleon Skousen, Isaiah Speaks to Modern Times [Salt Lake City: Ensign Publishing Co., 1984], 261.)