Ramayana
एवं बलिभ्यो बलिनः सन्ति राघवनन्दन । नावज्ञा हि परे कार्या य इच्छेत् प्रियमात्मनः ॥ 7-33-22 ॥
Even so, O delight of the Raghus, there are those stronger than the strong; one who desires his own welfare should never hold others in contempt.
english translation