2 Kings 3:26-27

26And when the king of Moab saw that the battle was too fierce for him, he took with him seven hundred men who drew swords, to break through to the king of Edom, but they could not.

27Then he took his eldest son who would have reigned in his place, and offered him as a burnt offering upon the wall; and there was great indignation against Israel. So they departed from him and returned to their own land.