Even though the author uses the plural pronoun "we," he is most likely referring only to himself. Alternate translation: "I have much to say" (See: [[rc://en/ta/man/translate/figs-pronouns]])
The ability to understand and obey is spoken of as if it were the ability to listen. And the ability to listen is spoken of as if it were a metal tool that becomes dull with use. Alternate translation: "you have trouble understanding it" (See: [[rc://en/ta/man/translate/figs-metaphor]])