The eyes represent seeing, and seeing represents thoughts or judgment. Alternate translation: "being wise in your own opinion" or "being wise according to your own judgement" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The writer uses this rhetorical question to emphasize that being self-righteous destroys a person. Alternate translation: "There is no reason to destroy yourself." or "If you think this way you will destroy yourself." (See: [[rc://en/ta/man/translate/figs-rquestion]])