Valmiki Ramayana Yuddha Kanda Sarga 6 Shloka 12
Original Shlokaऐकमत्यमुपागम्यशास्त्रदृष्टेनचक्षुषा ।।6.6.12।। मन्त्रिणोयत्रनिरतास्तमाहुर्मन्त्रमुत्तमम् ।
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मन्त्रिणः ministers, शास्त्रदृष्टेन: based on Sastras, चक्षुषा: in view, ऐकमत्यम् all of them come to one conclusion, उपागम्य: having come together, यत्र: then निरताः remain attached, तम् such, मन्त्रम् counsel, उत्तमम् best, आहु: said to be.
"When all ministers are unanimous and come to one conclusion based on sastras, and having come together remain firm, such counsel is said to be the best."