There will I make the horn of David to bud: I have ordained a lamp for mine anointed.
There will I make the horn of David to bud. "There" - namely, in Zion I will make David's race to rise from depression to eminence in kingly dignity (cf. Ezekiel 29:21). Luke 1:69 applies the prophecy to Messiah. A horn is the symbol of strength (Psalms 75:4, note).
I have ordained a lamp for mine anointed - I will cause the light of prosperity to shine again upon his race, after the darkness that has enveloped them, for the sake of David mine anointed. Compare the same image, Psalms 18:28. Especially 1 Kings 11:36, "Unto his (Solomon's) son will I give one tribe, that David my servant may have a light (Hebrew, lamp) alway before me in Jerusalem" (1 Kings 15:4; 2 Chronicles 21:7).