People who stubbornly refuse to understand what God is saying or doing are spoken of as if their heart is dull. Here "heart" is a metonym for the mind. (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-metonymy]])
# with their ears they hardly hear, and they have shut their eyes
People who stubbornly refuse to understand what God is saying or doing are spoken of as if they are unable to hear and are shutting their eyes so that they will see. (See: [[rc://en/ta/man/translate/figs-metaphor]])
# understand with their heart
Here "heart" stands for the mind. (See: [[rc://en/ta/man/translate/figs-metonymy]])
# turn again
To start obeying God is spoken of as though the person were physically turning toward God. (See: [[rc://en/ta/man/translate/figs-metaphor]])