Augustine of Hippo

(de Quæst. Evan. l. i. q. l.) Now here we must first consider that it is not likely that Zacharias, when offering sacrifice for the sins or for the salvation or redemption of the people, would neglect the public petitions, to pray (though himself an old man, and his wife also old) that he might receive children; and, next, above all that no one prays for what he despairs of ever obtaining. And even up to this time, sc much had he despaired of ever having children, that he would not believe, even when an angel promised it to him. The words, Thy prayer is heard, must be understood therefore to refer to the people; and as salvation, redemption, and the putting away of the sins of the people was to be through Christ, it is told Zacharias that a son shall be born to him, because that son was ordained to be the forerunner of Christ.