Shloka 2.107.12
पितृवाक्यपालनम्, गयाश्रुति-उपदेशः, भरतस्य राज्यग्रहण-निर्देशः (Rama’s Counsel on Vows, the Gaya Śruti, and Bharata’s Return to Rule)
पुन्नाम्नो नरकाद् यस्मात् पितरं त्रायते सुतः।तस्मात् पुत्र इति प्रोक्तः पितॄन् यः पाति सर्वतः।।2.107.12।।
punnāmno narakād yasmāt pitaraṃ trāyate sutaḥ | tasmāt putra iti proktaḥ pitṝn yaḥ pāti sarvataḥ ||
Since a son delivers his father from a hell called ‘Put’, therefore he is called putra—one who protects the ancestors in every way.
Putra is so called as he delivers his father from a hell known as Put and protects the ancestors in all possible ways.
Dharma is filial responsibility: the son bears a sacred duty to protect and uplift the father and ancestors through righteous conduct and rites.
Rāma cites a traditional explanation of the word putra to instruct Bharata on obligations toward ancestors.
Sense of duty (kartavya) toward lineage—continuity of dharma across generations.