कर्मणैव हि संसिद्धिमास्थिता जनकादय: |
लोकसंग्रहमेवापि सम्पश्यन्कर्तुमर्हसि || 20||
By performing prescribed duties, King Janaka and others attained the perfectional stage. Therefore, just for the sake of the welfare of the earth in general, you should perform your prescribed duties.
Bhagwan Shri Krishna explains to Arjuna about the perfect way to engage in the actions that are our responsibility. We must never stay inactive as that state only benefits the one who have attained the ultimate truth.
Bhagwan Shri Krishna goes further and elaborates that those who have realised the self or have attained the ultimate truth also engage in their action without any attachment. Bhagwan gives example of the King Janaka that how did he engaged in his worldly duty as a king.
He was completely detached from the actions that he performed and walking on this path with patience and detachment, he attained self realisation. Even after attaining the ultimate truth, he continued to perform his actions of a king.
Bhagwan Shri Krishna advices Arjuna that for setting a perfect example for the world to follow, Arjuna must perform his duty as a Kshatriya and fight this war. It will inspire the generations to come.