How can a man of God be an angel of God? A man is a man and an angel is an angel, right? Man is from below, Angels are from above, right?

Judges 13:3And the angel of the LORD appeared unto the woman, and said unto her, Behold now, thou art barren, and bearest not: but thou shalt conceive, and bear a son.

4Now therefore beware, I pray thee, and drink not wine nor strong drink, and eat not any unclean thing:

5For, lo, thou shalt conceive, and bear a son; and no razor shall come on his head: for the child shall be a Nazarite unto God from the womb: and he shall begin to deliver Israel out of the hand of the Philistines.

6Then the woman came and told her husband, saying, A man of God came unto me, and his countenance was like the countenance of an angel of God, very terrible: but I asked him not whence he was, neither told he me his name:

7But he said unto me, Behold, thou shalt conceive, and bear a son; and now drink no wine nor strong drink, neither eat any unclean thing: for the child shall be a Nazarite to God from the womb to the day of his death.

8Then Manoah intreated the LORD, and said, O my Lord, let the man of God which thou didst send come again unto us, and teach us what we shall do unto the child that shall be born.

9And God hearkened to the voice of Manoah; and the angel of God came again unto the woman as she sat in the field: but Manoah her husband was not with her.

10And the woman made haste, and ran, and shewed her husband, and said unto him, Behold, the man hath appeared unto me, that came unto me the other day.

11And Manoah arose, and went after his wife, and came to the man, and said unto him, Art thou the man that spakest unto the woman? And he said, I am.

12And Manoah said, Now let thy words come to pass. How shall we order the child, and how shall we do unto him?

13And the angel of the LORD said unto Manoah, Of all that I said unto the woman let her beware.

14She may not eat of any thing that cometh of the vine, neither let her drink wine or strong drink, nor eat any unclean thing: all that I commanded her let her observe.

15And Manoah said unto the angel of the LORD, I pray thee, let us detain thee, until we shall have made ready a kid for thee.

16And the angel of the LORD said unto Manoah, Though thou detain me, I will not eat of thy bread: and if thou wilt offer a burnt offering, thou must offer it unto the LORD. For Manoah knew not that he was an angel of the LORD.

17And Manoah said unto the angel of the LORD, What is thy name, that when thy sayings come to pass we may do thee honour?

18And the angel of the LORD said unto him, Why askest thou thus after my name, seeing it is secret?