Albert Barnes Commentary 1 Kings 17:18

"And she said unto Elijah, What have I to do with thee, O thou man of God? thou art come unto me to bring my sin to remembrance, and to slay my son!" — 1 Kings 17:18 (ASV)

What have I to do with thee? — that is, “What do we have in common?” — implying a further question, “Why have you not left me in peace?” The woman imagines that Elijah’s visit had drawn God’s attention to her, and so to her sins, which (she feels) deserve a judgment: her son’s death.

Thou man of God — In the mouth of the Phoenician woman, this expression is remarkable. Among the Jews and Israelites (1 Kings 12:22; Judges 13:6, 8), it seems to have become the ordinary designation of a prophet. We now see that it was understood in the same sense beyond the borders of the holy land.