Charles Ellicott Commentary Genesis 16:13

"And she called the name of Jehovah that spake unto her, Thou art a God that seeth: for she said, Have I even here looked after him that seeth me?" — Genesis 16:13 (ASV)

Thou God seest me. —Hebrew, You are El Roi, that is, a God of seeing. Not as Onkelos paraphrases it, “You are a God that sees all things,” but “You are a God that permits Himself to be seen.”

For Hagar herself proceeds to explain the name, Do I not still see after seeing? With all the love of an Easterner for enigmatic sayings, Hagar plays upon the word “roï,” but her meaning is plain: “Do I not see, and therefore am alive, and not even blinded, nor deprived of sense and reason, though I have seen God.”