The appearances of angels are different purposely as to different persons and occasions.
The appearance of an angel to Moses was as follows: When Moses was a shepherd in the desert, the angel of the Lord appeared unto him in a flame of fire out of the midst of a bush; and he looked, and, behold, the bush burned with fire, and the bush was not consumed. And God called unto him out of the midst of the bush, and said, "Moses, Moses" (Ex. 3:2,4). Moses saw no face and no figure but the fire, and out of the fire he heard the voice calling him and instructing him as to what to do.
The appearance to whole people of Israel, when they fled from Egypt: And the Lord went before them by day in a pillar of a cloud, …and by night in a pillar of fire, to give them light (Ex. 13:21).
This was not the Lord Himself but His angel. Moses confirms that: When we cried unto the Lord, He heard our voice, and sent an angel, and hath brought us forth out of Egypt (Num. 20:16). Here, as somewhere else, the angel is identified with the Lord, God. For My name is in him, says the Lord God (cf. Ex. 23:2021).
To Gideon an angel appeared as an ordinary man, just as the Archangel Raphael appeared to Tobias. Gideon understood that it was an angel only he saw a miracle performed by his unknown visitor. Then he exclaimed: Alas, O Lord God! For I have seen an angel of the Lord face to face (Judges 6:12-23).
To the wife of Manoah, who was barren and childless, an angel appeared with the news that she would have a son, Samson by name. Recounting this event to her husband, she said: A man of God came unto me, and his countenance was like the countenance of an angel of God, very terrible (Judges 13:6).
When the Syrians surrounded the place where the prophet Elisha lived, his frightened servant exclaimed: Alas, how shall we do? And Elisha answered: Fear not, for they that be with us are more then they that be with them.
And by the prayers of Elisha, the Lord opened the eyes of the young man; and the he saw: and, behold, the mountain was full of horses and chariots of fire around about Elisha (II Kings 6:16-17). Of course, that was the host of God's angels sent to protect the righteous man.
To the prophet Ezekiel the angel was as the appearance of fire: from his loins even downward, fire: and from his loins even upward, as appearance of brightness, as the color of amber (Ezekiel 8:2).
The great prophet Daniel saw an angel as a certain man clothed in linen, whose loins were girded with fine gold of Uphaz. His body also was like the beryl and his face as the appearance of lightning, and his eyes as lamps of fire, and his arms and his feet like in color to polished brass, and the voice of his words like the voice of a multitude. So much was Daniel frightened that he says: Therefore I was left alone …and there remained no strength in me …and I retained no strength (Dan. 10:8). It was Archangel Gabriel (Dan. 8:16).
The same Gabriel appeared to Zacharias, the father of St. John the Baptist. And though his appearance was not so terrifying as that which Daniel saw, yet Zacharias, when he saw him, was troubled and fear fell upon him. And the angel said unto him: Fear not, Zacharias! (Luke 1:12-13).
As to the appearance of Gabriel to the Virgin Mary at Nazareth, we presume that the appearing was in a gentle human form, unlike those terrifying forms in which the angels appeared to the prophets of old. Yet, Mary was frightened and troubled. No wonder, for not only in extraordinary appearance frightens us, but also the suddenness of it. The angel therefore encouraged the Holy Virgin by saying: Fear not, Mary! (Luke 1:29030).
When our Lord Jesus was born, an angel appeared to the shepherds at Bethlehem. And, lo, the angel of the Lord came upon them, and the glory of the Lord shone round about them: and they were sore afraid. And the angel said unto them: Fear not (Matt. 28:3-5).
The myrrh bearing women at the sepulcher of the risen Lord saw an angel: His countenance was like lightning, and his raiment white as snow: And for fear of him the keepers (of the tomb) did shake, and became as dead men. To the women, however, the angel said: Fear not ye! (Matt. 28:3-5).
In no other sacred book is so much written about angels as in the Book of Revelation. St. John saw a multitude around the throne of the Highest. He describes them as clad in pure and white linen, having their breasts girded with golden girdles (Rev. 15:6). Very striking is the description of one of them: I saw, says John, another mighty angel came down from heaven, clothed with a cloud: and a rainbow was upon his head, and his face was as it were the sun, and his feet as pillars of fire …And he cried with a loud voice, as when a lion roareth (Rev. 10: 1, 3).
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