PROOF OF OUR LORD'S DIVINITY taken from the angel's words. Firstly, Gabriel said that Jesus was the "Son of the most High" and the "Son of God." Secondly, he said that Jesus should "save His people from their sins." Now, God alone can redeem from sin; therefore Jesus must be God.
[From 'A Practical Commentary on Holy Scripture' by Bishop Knecht, D.D.]
(1899 Douay-Rheims Bible)