Valmiki Ramayana Yuddha Kanda Sarga 1 Shloka 8
Original Shlokaनियुक्तोय: परं कार्यं न कुर्यान्नृपतेः प्रियम् । भृत्योऽभृत्यस्समर्थोऽपि तमाहुर्मध्यमं नरम् ।।6.1.8।।
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यः he, भृत्यः is a servant, समर्थ: efficient, अभृत्य: not a servant, नियुक्तः told, नृपते: by king, प्रियम्: dear, कार्यम्: work, परम्: other, नकुर्यात्: does not do, तम्: him, नरम्: mediocre, अहु: said to be
An efficient servant does not only do what is asked but also does the work dear to the king. One who does not do so is said to be mediocre.