And the angel of the Lord appeared unto the woman
According to Josephus F11, it was in a plain without the city; and that he appeared in the form of a man is certain from ( Judges 13:6 ) but was not a mere man, a prophet of the Lord, nor a created angel, but the uncreated one, the Angel of the covenant, the Son and Word of God, who often appeared in an human form; since his name is said to be "Wonderful", and he to do wonderful things, and is called "Jehovah", ( Judges 13:18 Judges 13:23 ) ,
and said unto her, behold now, thou art barren, and bearest not;
barren at that time, and so she had been ever since she was married to that time; and this is observed, that it might appear the more wonderful that she should after this have a child:
but thou shalt conceive, and bear a son;
which to do, must be ascribed to divine power, that one in her circumstances should bear a son; as the prediction of it was owing to divine omniscience, and a proof of it.