Never argue with a fool

प्रसह्य मणिमुद्धरेन्मकरवक्त्रदंष्ट्रान्तरात्
समुद्रमपि सन्तरेत्प्रचलदूर्मिमालाकुलम् ।
भुजङ्गमपि कोपितं शिरसि पुष्पवद्धारयेत्
न तु प्रतिनिविष्टमूर्खजनचित्तमाराधयेत् ॥

- नीतिशतकम्

It may be possible to forcibly snatch a jewel from the midst of powerful jaws of a crocodile. It may also be possible to cross a raging sea swimming across its high-running violent waves. One may even wear a furious snake around his head as if it is a garland of flowers. But it is impossible to win over a conceited fool!

Every evil has its remedy, except folly.
Never argue with a fool; people might not be able to tell the difference.