Lactantius, The Divine Institutes, Book IV. Of True Wisdom and Religion Chapter VII. Of the Name of Son, and Whence He is Called Jesus and Christ.
Some one may perhaps ask who this is who is so powerful, so beloved by God, and what name He has, who was not only begotten at first before the world, but who also arranged it by His wisdom and constructed it by His might. First of all, it is befitting that we should know that His name is not known even to the angels who dwell in heaven, but to Himself only, and to God the Father; nor will that name be published, as the sacred writings relate, before that the purpose of God shall be fulfilled. In the next place, we must know that this name cannot be uttered by the mouth of man, as Hermes teaches, saying these things: “Now the cause of this cause is the will of the divine good which produced God, whose name cannot be uttered by the mouth of man.” And shortly afterwards to His Son: “There is, O Son, a secret word of wisdom, holy respecting the only Lord of all things, and the God first perceived by the mind, to speak of whom is beyond the power of man.” But although His name, which the supreme Father gave Him from the beginning, is known to none but Himself, nevertheless He has one name among the angels, and another among men since He is called Jesus among men: for Christ is not a proper name, but a title of power and dominion; for by this the Jews were accustomed to call their kings. But the meaning of this name must be set forth, on account of the error of the ignorant, who by the change of a letter are accustomed to call Him Chrestus. The Jews had before been directed to compose a sacred oil, with which those who were called to the priesthood or to the kingdom might be anointed. And as now the robe of purple is a sign of the assumption of royal dignity among the Romans, so with them the anointing with the holy oil conferred the title and power of king. But since the ancient Greeks used the word χρίεσθαι to express the art of anointing, which they now express by ἀλείφεσθαι, as the verse of Homer shows,
“But the attendants washed, and anointed (χρισαν) them with oil;”
on this account we call Him Christ, that is, the Anointed, who in Hebrew is called the Messias. Hence in some Greek writings, which are badly translated from the Hebrew, the word eleimmenos is found written, from the word aleiphesthai, anointing. But, however, by either name a king is signified: not that He has obtained this earthly kingdom, the time for receiving which has not yet arrived, but that He sways a heavenly and eternal kingdom, concerning which we shall speak in the last book. But now let us speak of His first nativity.