The phrases "stiffened his neck" and "hardened his heart" are both metaphors that mean to become stubborn. Zedekiah refusing to worship Yahweh is spoken of as if he refused to turn to Yahweh. AT: "Zedekiah stubbornly refused to worship Yahweh" (See: [[rc://en/ta/man/translate/figs-doublet]] and [[rc://en/ta/man/translate/figs-metaphor]])
The idiom "followed the ... practices" means to do those things. AT: "they did the disgusting things that the nations did" (See: [[rc://en/ta/man/translate/figs-idiom]])
A place that is unfit to be used for God's purposes is spoken of as if it were physically dirty. The word "house" represents the temple. AT: "They polluted the temple of Yahweh" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-metonymy]])