Albert Barnes Commentary Nahum 3:7

"And it shall come to pass, that all they that look upon thee shall flee from thee, and say, Nineveh is laid waste: who will bemoan her? whence shall I seek comforters for thee?" — Nahum 3:7 (ASV)

All those who look upon you will flee from you - through terror, lest they share her plagues, as Israel did when the earth swallowed up Korah, Dathan, and Abiram; and those who “had been made rich by Babylon, stand ajar off, for the fear of her torment. All those who look on you” (Revelation 18:15).

She was set as a thing to be “gazed at.” He tells the effect on the gazers. “Each one who so gazed” at her should flee; one by one, they should gaze, be scared, flee (Psalms 64:8).

Not one should remain. Who will bemoan her? Not one should pay her the passing tribute of sympathy at human calamity, the shaking of the head at her woe . Whoever had no compassion will find none.