Jamieson, Fausset & Brown

horn of salvation--that is "strength of salvation," or "mighty Salvation," meaning the Saviour Himself, whom Simeon calls "Thy Salvation" (Luk 2:30). The metaphor is taken from those animals whose strength is in their horns (Psa 18:2; Psa 75:10; Psa 132:17). house of . . . David--This shows that Mary must have been known to be of the royal line, independent of Joseph; of whom Zacharias, if he knew anything, could not know that after this he would recognize Mary.