Now it escaped the notice of Celsus, and of the Jew whom he has introduced, and of all who are not believers in Jesus, that the prophecies speak of two advents of Christ: the former characterized by human suffering and humility, in order that Christ, being with men, might make known the way that leads to God, and might leave no man in this life a ground of excuse, in saying that he knew not of the judgment to come; and the latter, distinguished only by glory and divinity, having no element of human infirmity intermingled with its divine greatness.
To quote the prophecies at length would be tedious; and I deem it sufficient for the present to quote a part of the forty-fifth Psalm, which has this inscription, in addition to others, “A Psalm for the Beloved,” where God is evidently addressed in these words: “Grace is poured into Your lips: therefore God will bless You for ever and ever. Gird Your sword on Your thigh, O mighty One, with Your beauty and Your majesty. And stretch forth, and ride prosperously, and reign, because of Your truth, and meekness, and righteousness; and Your right hand shall lead You marvellously.
Your arrows are pointed, O mighty One; the people will fall under You in the heart of the enemies of the King.” But attend carefully to what follows, where He is called God: “For Your throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of Your kingdom. You have loved righteousness, and hated iniquity: therefore God, even Your God, has anointed You with the oil of gladness above Your fellows.” And observe that the prophet, speaking familiarly to God, whose “throne is for ever and ever,” and “a sceptre of righteousness the sceptre of His kingdom,” says that this God has been anointed by a God who was His God, and anointed, because more than His fellows He had loved righteousness and hated iniquity.
And I remember that I pressed the Jew, who was deemed a learned man, very hard with this passage; and he, being perplexed about it, gave such an answer as was in keeping with his Judaistic views, saying that the words, “Your throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of Your kingdom,” are spoken of the God of all things; and these, “You have loved righteousness and hated iniquity, therefore Your God has anointed You,” etc., refer to the Messiah.
Source: Against Celsus (New Advent)