We are introduced to the first appearances of angels in the Bible when an angelic visitation took place with an Egyptian slave girl named Hagar who had fled Abraham’s house after conflict with Sarai, Abraham’s wife.  (Gen 16:7-12

Gen 16:7-12 And the angel of the LORD found her by a fountain of water in the wilderness, by the fountain in the way to Shur.
8 And he said, Hagar, Sarai's maid, whence camest thou? and whither wilt thou go? And she said, I flee from the face of my mistress Sarai.
9 And the angel of the LORD said unto her, Return to thy mistress, and submit thyself under her hands.
10 And the angel of the LORD said unto her, I will multiply thy seed exceedingly, that it shall not be numbered for multitude.
11 And the angel of the LORD said unto her, Behold, thou art with child, and shalt bear a son, and shalt call his name Ishmael; because the LORD hath heard thy affliction.
12 And he will be a wild man; his hand will be against every man, and every man's hand against him; and he shall dwell in the presence of all his brethren.KJV

The angel told Hagar to return to Abraham’s house.  He told her God would multiply her seed exceedingly.  He revealed she was going to give birth to a son she should name Ishmael and also revealed what kind of man he would be and his future.