(Isa. 50:5)
Part of the ceremony of consecration of Aaron, in the Mosaic dispensation, was the application of a drop of sacrificial blood to the right ear, to signify his willingness to hear and obey the laws of God (Ex. 29:20). A similar ceremony, with the same import, was part of the healing of a leper. (Lev. 14:14). The “servant” in this paragraph, therefore, says that the Lord had healed him, giving him the Priesthood, and made him willing to obey. This is particularly true in our day when the restored Gospel is received chiefly by those in whose veins the blood of Israel is flowing.
(George Reynolds and Janne M. Sjodahl, Commentary on the Book of Mormon, 7 vols., ed. Philip C. Reynolds [Salt Lake City: Deseret book Co., 1955–1961], 1:286.)