Hath my master... — Rather, Is it to thy lord and to thee that my lord hath sent me to speak these words?
The men which sit on the wall — i.e., the soldiers on guard.
That they may eat ... — These coarse words are meant to express the consequence of their resistance: it will bring them to such dire straits that they will be fain to appease the cravings of hunger and thirst with the vilest garbage. (Comp. 2 Kings 6:25 seq.)