Shloka 4.43.59
सुग्रीवस्य शतवलि-प्रेषणम् (Sugriva’s Commission to Satavali for the Northern Search)
न कथञ्चन गन्तव्यं कुरूणामुत्तरेण वः।अन्येषामपि भूतानां नातिक्रामति वै गतिः।।।।
kṛtaṃ hi priyam asmākaṃ rāghaveṇa mahātmanā | tasya cet pratikāro 'sti saphalaṃ jīvitaṃ bhavet ||
The great-souled Rāghava has already done us a cherished service; if there is any way to repay him, then our very lives will become meaningful.
'You should not go beyond the north of Kuru. No living being can trespass it.
Kṛtajñatā—remembering a benefit received and striving to repay it—is presented as dharmic conduct that makes one’s life ‘fruitful’.
Sugrīva motivates the vānara search parties to exert themselves in Sītā’s search by recalling Rāma’s prior help to their cause.
Gratitude and responsibility: the willingness to return a favor through committed action.