हत्वेव ब्राह्मणं कामात्स्पृष्ट्वाग्निमिव पाणिना।
अन्वतप्यत धर्मात्मा पुत्रं सञ्चिन्त्य तापसम्॥
hatveva brāhmaṇaṁ kāmāt spṛṣṭvāgnim iva pāṇinā
anvatapyata dharmātmā putraṁ sañcintya tāpasam
hatvā = struck; iva = like one who had; brāhmaṇam = a brāhmaṇa; kāmāt = intentionally; spṛṣṭvā = touched; agnim = fire; iva = and like one who had; pāṇinā = with his hand; anvatapyata = repented; dharma-ātmā = Daśaratha of a dhārmika mind; putram = about his son; sañcintya = while thinking; tāpasam = who had put on the dress of an ascetic.
Like one who had intentionally struck a brāhmaṇa and like one who had touched fire with his hand, Daśaratha of a dhārmika mind repented while thinking about his son who had put on the dress of an ascetic.1
1 Technical note: hanas tāḍanārthakatvaṁ mālā-hata iva dvipa ity-ādau. This is a reference to Śrīmad-Bhāgavatam 10.44.22 and 10.59.20. Hatvā in the current Rāmāyaṇa verse cannot mean “having killed,” for later on in this very Canto the king will lament even more than now while recollecting how he had unintentionally killed a brāhmaṇa boy which is definitely less worse than intentionally killing a brāhmaṇa.