Isaiah 14:30

And the firstborn of the poor shall feed
That is, the Jews, who were brought very low in the times of Ahaz, reduced to the greatest straits and difficulties; for so the word "firstborn" may signify the chief, or those who were of all the poorest, and in the greatest distress; these, in the times of Hezekiah, shall enjoy abundance of good things, and under his gentle government shall feed like a flock of sheep in good pastures; this signifying, that though he should be like a serpent, harmful to his enemies, yet should be kind and tender unto, and take great care of his own subjects, and under whom they should have great plenty and prosperity: and the needy shall lie down in safety;
like a flock of sheep, secure from beasts of prey, under the care of a faithful and vigilant shepherd; this shows that the Jews should not only have plenty of good things, but should live in the greatest security, without fear of any enemy, or danger from them: and I will kill thy root with famine;
this is said to Palestine, compared to a tree, whose root is dried up for want of moisture, and so dies; and the meaning is, that a sore famine should rage in their country, and utterly destroy them: and he shall slay thy remnant:
that is, Hezekiah should slay with the sword those that were left of the famine.