The Ramayan by Valmiki

Then Ravan spake with flashing eye: "Hence with the Vanar: let him die." Vibhishan heard the stern behest, And pondered in his troubled breast; Then, trained in arts that soothe and please Addressed the king in words like these: "Revoke, my lord, thy fierce decree, And hear the words I speak to thee. Kings wise and noble ne'er condemn To death the envoys sent to them. Such deed the world's contempt would draw On him who breaks the ancient law. Observe the mean where justice lies, And spare his life but still chastise." Then forth the tyrant's fury broke, And thus in angry words he spoke: "O hero, when the wicked bleed No sin or shame attends the deed. The Vanar's blood must needs be spilt, The penalty of heinous guilt."

Again Vibhishan made reply: "Nay, hear me, for he must not die. Hear the great law the wise declare: "Thy foeman's envoy thou shalt spare." 'Tis true he comes an open foe: 'Tis true his hands have wrought us woe, But law allows thee, if thou wilt, A punishment to suit the guilt. The mark of shame, the scourge, the brand, The shaven head, the wounded hand. Yea, were the Vanar envoy slain, Where, King of giants, were the gain? On them alone, on them who sent The message, be the punishment. For spake he well or spake he ill, He spake obedient to their will, And, if he perish, who can bear Thy challenge to the royal pair? Who, cross the ocean and incite Thy death-doomed enemies to fight?"