The Nunc dimittis is driven by Simeon’s use of “now.” “Not tomorrow. Not next week. Not yesterday, Lord, but now, let your servant depart in peace.” The “now” of Simeon was radically different from the “now” of Bultmann. For thinkers such as Bultmann, salvation occurs in the hit et nunc, not horizontally in the plane of history, but vertically; Immediately, out of the sky, God hits you in the moment with His Word, and you have this existential experience which then begins to define your life. This is, at best, theologically inaccurate. God’s justification of His own may be momentary, but it is grounded in His election from before time began (II Timothy 1:9-10).
When Simeon said “now,” he didn’t mean it in a vertical, existential, mythological sense. He meant now chronologically, now historically, because he was convinced that the redemption that God was bringing to pass in that moment was not something that simply happened today, but was rooted and grounded in hundreds, indeed thousands of years of history. Simeon, a devout and knowledgeable Jewish temple worker, likely though back to the first proclamation of the gospel — a cryptic revelation ironically given in the context of a curse of Satan. In the garden of Eden, when the Lord placed His curse upon the serpent, He said that the seed of the woman would have His heel bruised by the seed of the serpent, but that the seed of the woman would crush the head of the serpent (Genesis 3:14-15). Adam and Eve didn’t respond to the Lord by saying “Now? Today?” Of course not; God’s word would come to pass later. It would happen in space and time, but yet.
Through the progression of the whole Old Testament, from the promises given to Abraham, Isaac and Jacob, to the sacrificial system instituted in the Old Testament, with the Day of Atonement, the tabernacle and all its accoutrements, God’s people were reminded of the future when God would visit the earth in the person of His Son: the Messiah. The people waited, prayed, hoped and went through the processes that the LORD had prescribed, all of them pointing beyond themselves to a future known in history when God personally would come to redeem His people. The Psalms of David look forward to that Messianic event, and David himself was thought by many perhaps to be the embodiment of Messiah. He was perhaps the greatest king Israel ever had, but his monarchy failed. But God spoke through the prophet to say that when the Messiah comes, David’s booth would be restored, its breaches repaired, and a King would sit on that throne forever (Amos 9:11-15). This coming Messiah would be David’s son and David’s Lord.