Verse 21

मा खेदं भज हेयेषु नोपादेयपरो भव ।हेयादेयदृशौ त्यक्त्वा शेषस्थः स्वच्छतां व्रज

In plain words

Do not give way to grief over what is to be rejected; do not become intent on what is to be taken up. Abandon both these ways of seeing — the rejected and the accepted — and, abiding as what remains beyond them, go to clarity.