Valmiki Ramayana Ayodhya Kanda Sarga 21 Shloka 22
Original Shlokaधर्मज्ञ यदि धर्मिष्ठो धर्मं चरितुमिच्छसि। शुश्रूष मामिहस्थस्त्वं चर धर्ममनुत्तमम्।।2.21.22।।
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धर्मज्ञ O knower of duties, धर्मिष्ठः pious, धर्मम् righteousness, चरितुम् to follow, इच्छसि यदि if you wish, त्वम् you, इहस्थः by staying here, माम् me, शुश्रूष serve, अनुत्तमम् best, धर्मम् of virutes, चर follow.
You are righteous. You know your duty. If you wish to follow the path of righteousness, stay here, serve me and follow the best of dharma.