Devibhagavatapurana 2.5.33

2.5.33

sūta uvāca |
śrutvāvākyaṃ tu dāśasya rājā cintāturo'bhavat |
gāṅgeyaṃ manasā kṛtvā novāca nṛpatistadā ||

Hearing these words of the fisherman, the king S’antanu became very anxious. He remembered Gângeya and could not speak anything. He, being sick with love anxiously returned home; but he abandoned bathing, fooding, sleeping, etc. At this, the son Gângeya Bhîsma whose vow was equal to that of the gods, marking that the king was being troubled with some thought, went to him and asked why he was anxious:-- “O king! Say truly what is your anxiety; who is your enemy that is not conquered; whom do you went to bring under your control? O king! What use is there of having a son who does not understand the difficulties of his father, or does not try to remove these difficulties. A son can be called really the son, who is born to repay the debts incurred by him in previous births; there is no manner of discussion in this. See, Raghu's son Dâsarathî Râm abandoned his kingdom under the orders of his father and repaired to Chitrakûta forest with his brother Laksman and wife Sîtâ. The son of king Haris Chandra, Rohîta, ready to repay the debt of his father and sold by his father, worked as a servant at a Brâhmana's house. So the famous S’unahs'ephah, sold by his high souled father Ajigarta was tied for sacrifice in a sacrificial post; but he was afterwards freed by the Gâdhi's son Vis'vâmitra.