(Isa. 49:6; 42:6; D&C 86:11; Luke 2:25–32)
How could the Holy One of Israel—who is sinless and perfect, and who is the same everlastingly—come into mortality without remaining as the Sinless One and therefore being a light and an example to all men? If the Great Jehovah … was destined to make flesh his tabernacle, how could he do other than bring with him the effulgent light and glory which dwelt in his person? …
The prophetic word abounds in such statements as: “The Lord is my light and my salvation.” (Ps. 27:1.) “O send out thy light and thy truth: let them lead me.” (Ps. 43:3.) “God is the Lord, which hath shewed us light.” (Ps. 118:27.) “Thy word is a lamp unto my feet, and a light unto my path.” (Ps. 119:105.) None can doubt that the Jewish Jehovah who led their fathers was himself the source of light and truth for all.
With reference to his future Messianic ministry, his ministry among mortals as the Son of God, it is written: “I will also give thee for a light to the Gentiles, that thou mayest be my salvation unto the end of the earth.” (Isa. 49:6.)
(Bruce R. McConkie, The Mortal Messiah, 4 vols. [Salt Lake City: Deseret Book Co., 1979–1981], 3:147.)
His hearers well knew that their Messiah should stand as a light to all men; that is, they knew that he as the very source of light and truth, would stand forth as a light, an example, a dispenser of truth… . Messianic prophecies given to their fathers promised that he would be “a light to the Gentiles.”
(Bruce R. McConkie, Doctrinal New Testament Commentary, 3 vols. [Salt Lake City: Bookcraft, 1966–1973], 452–53.)
God’s servant not only will gather and restore the descendants of Abraham but will also reach out to the Gentiles. Thus salvation will reach “unto the end of the earth.” The light to the Gentiles is variously defined in the scriptures as Jesus Christ (Isa. 42:6–7; Luke 2:32), the priesthood (D&C 86:11), and Zion (60:3). If the servant referred to in this section is not the Messiah himself, he certainly will shine with the light of the Messiah.
(Donald W. Parry, Jay A. Parry, and Tina M. Peterson, Understanding Isaiah [Salt Lake City: Deseret Book Co., 1998], 427.)