पञ्चतंत्र - मित्रभेद - स्वभाव

स्वभावो नोपदेशेन शक्यते कर्तुमन्यथा |
सुतप्तमपि पानीयं पुनर्गच्छति शीतताम् ||

- पञ्चतंत्र - मित्रभेद

Objects or people will always follow their innate disposition. It can not be changed by any amount of advice. No matter how much heat water, left to itself, it will cool down.

- Panchatantra, Mitrabhedha