Valmiki Ramayana Ayodhya Kanda Sarga 52 Shloka 79
Original Shlokaआचम्य च यथाशास्त्रं नदीं तां सह सीतया। प्राणमत्प्रीतिसंहृष्टो लक्ष्मणश्चामितप्रभः।।2.52.79।।
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सीतया सह along with Sita, यथाशास्त्रम् as per the scriptures, आचम्य च sipping (the water of Ganga), प्रीतिसंहृष्टः with great pleasure, तां नदीम् that river, प्राणमत् paid obeisance, अमितप्रभः of unlimited radiance, लक्ष्मणश्च Lakshmana also.
Rama of undimmed radiance sipped the waters (of the Ganga) in accordance with the scriptures and with great pleasure and paid obeisance to the river with Sita and Lakshmana.