The people refusing to hear and obey Yahweh are compared to their being as unyielding as rock. Here the heart represents the will of a person. Alternate translation: "They stubbornly refused to hear the law or the words of Yahweh of hosts" (See: [[rc://en/ta/man/translate/figs-simile]])
Here the "mouth of the prophets" is a metonym for the words that the prophets speak. Alternate translation: "through the words of the prophets" (See: [[rc://en/ta/man/translate/figs-metonymy]])