A.T. Robertson Commentary Luke 1:69

"And hath raised up a horn of salvation for us In the house of his servant David" — Luke 1:69 (ASV)

Horn of salvation (κερας σωτηριας). A common metaphor in the O.T. (1 Samuel 2:10; 2 Samuel 23:3, etc.). It represents strength like the horns of bulls. Cf. Ps. 132:17.