Ramayana 2.34.32

न हि सत्यात्मनस्तात धर्माभिमनस स्तव।विनिवर्तयितुं बुद्धिः शक्यते रघुनन्दन।।।।

na hi satyātmanas tāta! dharmābhimanasa stava | vinivartayituṃ buddhiḥ śakyate raghunandana ||

For you, dear child—whose very self is truth and whose mind is set upon dharma—cannot easily be turned back from your resolve, O delight of the Raghus.