Here "heart" represents the mind or thoughts of a person. The idiom "his heart set against" means to be determined to oppose something. This can be stated as a new sentence. Alternate translation: "riches. He will be determined to oppose the holy covenant" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-idiom]])
The king's desire to act against the holy covenant represents his desire to stop the Israelites from obeying that covenant. Alternate translation: "determined to stop the Israelites from obeying the holy covenant" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "holy" describes God's covenant with Israel. It implies that the covenant should be honored and obeyed because it comes from God himself. Alternate translation: "God's covenant, which all the Israelites should obey"
This implies that the king will do certain actions in Israel. Alternate translation: "He will do what he wants to in Israel" (See: [[rc://en/ta/man/translate/figs-explicit]])