हितोपदेश - क्रिया फलम्

नाद्रव्ये निहिता काचित्क्रिया फलवती भवेत् ।
न व्यापारशतेनापि शुकवत्पाठ्यते बकः ॥

- हितोपदेश

nAdravye nihitA kAchit kriyA phalavatI bhavet ।
na vyApAra shatena api shikavat pAThyate bakaH ॥

- hitopadesha

One must not expend effort in trying to improve something that does not deserve the efforts (or simply can not change). No matter how hard you try, you can not teach a duck the same tricks you teach a parrot.

- Hitoapadesha