Here is the Sanskrit anuvad, Hindi anuvad, and English translation of Karma Yoga Chapter 3, Verse 3.20.
Sanskrit
कर्मणैव हि संसिद्धिमास्थिता जनकादयः । लोकसंग्रहमेवापि संपश्यन्कर्तुमर्हसि ॥ ३.२० ॥
Hindi
जनकादि ज्ञानीजन भी आसक्तिरहित कर्मद्वारा ही परम सिद्धिको प्राप्त हुए थे। इसलिये तथा लोकसंग्रहको देखते हुए भी तू कर्म करनेको ही योग्य है अर्थात् तुझे कर्म करना ही उचित है|
English
Wise men, such as King Janak, all attained the state of perfection by doing their duties and actions without any feelings of attachment to anyone or anything. Therefore, Arjuna, keeping in mind the goodwill and welfare of others in the world, do your duties and perform your actions selflessly.