Hail full of grace! The Lord is with you. This salute of Mary by the angel Gabriel has formed the first part of one of the most popular and iconic prayers that we should all be familiar with as Catholics, the  Hail Mary. Since the  Hail Mary is a prayer that we perhaps say on a daily basis, we join the angel Gabriel in saluting to posterity our Mother Mary using these words. And precisely because of this, this angelic greeting has perhaps come to lose its sting. It is even probable that those of us who repeat the words almost on a daily basis fail to appreciate the weight they carried when the angel Gabriel first uttered them. The Gospel account reports that when Mary heard those words, she was startled, and rightly so! The greeting was a very unusual one. As a matter of fact, it was more than a greeting. The angel was making a statement, and a very pregnant one at that. It was not a mere insinuation that the angel was making. It was a fact that he was stating. It was a very unusual manner of greeting someone, and Mary wanted to know why.
Mary was startled by angel Gabriel’s words because it was a salutation that had to be “backed up.” It was a salutation whose claim had to be “seen,” so to speak. For to say that the Lord was with someone was to say, literally speaking, that the Lord had come to have fellowship with the individual. However,  being with creatures was not the Lord’s  normal way of conducting business. The Lord’s “office” made it difficult for him to have fellowship with mortals. It is true there were instances in the history of Mary’s community when the Lord had visited certain individuals and had fellowship with them to the extent of referring to them as his friends. However, those instances were an exception rather than the norm. Moreover, those individuals that the Lord visited were in a way  superhuman. Those who walked with the Lord were no ordinary men and women. Mary was a mere ordinary teenager. Why would the Lord want her friendship?
To say that the Lord was with a people or with a person meant a lot of things. It meant that a people had been found worthy to host the Lord. It meant that a people had been found worthy to have fellowship (communion) with the Lord. It also meant that the Lord was the  peer of the individual he was with. In the case of Mary, it also meant that the Lord wanted to give her a responsibility because of her wisdom and holiness. But Mary was a mere teen, and there were more “holier” and “wiser” men and women in her village/community with whom the Lord could have communion. Something was wrong. Perhaps the angel had mistaken her for someone else. 
The angel Gabriel was not mistaken. It was to Mary that he had been sent with the good news of the Lord’s visitation. But the good news was not solely Mary’s. Mary was merely a conduit for the good things the Lord had planned to do for his people. As Mary would later say in her song of praise, the greeting was intended for the entire human race (children of Abraham). As the new Eve, Mary received the angel’s greeting on behalf of her children. She received the good news on behalf of her brothers and sisters. And when she said YES, she was speaking for us for she was aware that the time was nigh for the Lord to be with his people. 
The angel referred to Mary as full of grace because the Lord’s visitation is always a moment of grace. The Lord chooses those he wants to have fellowship with and then graces them for the occasion. Since the Lord’s visitation of Mary was a foreshadow of the Lord’s visitation of his people, it also follows that the goal of the Lord visiting his people was nothing other than to endow them with the graces that had been lost through humanity’s rebellion. It is this fact that makes the Christmas celebrations that we are awaiting a special one.