The metonym "Judah" represents the people of Judah. Yahweh humiliating the people is spoken of as if he physically brought Judah low to the ground. AT: "Yahweh humiliated the people of Judah because of Ahaz" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-metaphor]])
Ahaz sinning very much is spoken of as if sin were a very heavy object. AT: "sinned very greatly against Yahweh" (See: [[rc://en/ta/man/translate/figs-metaphor]])