Shloka 5.1.113
समुद्रलङ्घनारम्भः — Commencement of the Ocean-Crossing
राघवस्य कुले जातैरुदधिः परिवर्धितः।स त्वां रामहिते युक्तं प्रत्यर्चयति सागरः।।।।
rāghavasya kule jātair udadhiḥ parivardhitaḥ | sa tvāṁ rāma-hite yuktaṁ pratyarcayati sāgaraḥ ||
“The ocean was once enlarged by those born in Rāghava’s line; therefore Sāgara now returns that honor to you, since you are devoted to Rāma’s welfare.”
"The son of Rama's family, Sagara, has extended the ocean in the past.It is most appropriate that he (the god of the sea) honours you in return as you have set out in the service of Rama.
Kṛtajñatā (gratitude) and reciprocity: when good is received, dharma calls for an honoring return, especially toward those serving righteousness.
Maināka explains that the ocean, indebted to Rāma’s lineage, is now honoring Hanumān who acts for Rāma’s cause.
Kṛtajñatā (thankfulness): the ocean’s intent to repay a prior benefit through hospitality to Hanumān.