Valmiki Ramayana Yuddha Kanda Sarga 63 Shloka 10
Original Shlokaत्रिषुचैतेषुयच्छ्रेष्ठंश्रुत्वातन्नावबुध्यते । राजावाराजमात्रोवाव्यर्थंतस्यबहुश्रुतम् ।।6.63.10।।
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राजावा king or, राजमात्रोवा equal to king, एतेषु of these, त्रिषु three, यत् that, श्रेष्ठम् best, श्रुत्वा hearing, तत् that, नावबुध्यते not recognize it, तस्य his, बहु many, श्रुतम् heard, व्यर्थम् is in vain.
" A sovereign king or a king hearing these three does not recognize the best of the three is in vain even though he heard many."