The truth that is suppressed by friends is the readiest weapon of the enemy.

Stevenson’s aphorism warns that loyalty can become harmful when it turns into concealment. If friends withhold an uncomfortable truth—about one’s conduct, errors, or vulnerabilities—they deprive the person of the chance to correct course. What is hidden within a circle of goodwill often remains real and discoverable; when it surfaces publicly, an opponent can exploit it with maximum force because it arrives as a revelation rather than a managed admission. The line therefore argues for candid friendship: honest counsel is a form of protection, while flattering silence can unintentionally arm adversaries. It also implies a moral dimension: integrity and transparency reduce the leverage of hostile scrutiny.