In a society where rights are given more importance than duties, this line beautifully depicts the essence of Ramayana.
Do your duty. Yes Krishna tells it explicitly in MB, but the way it is done we have to understand Ramayana itself.
Personal pain, grief is at one side. But your duty is on the other side. No personal emotion can come in the way of performing your duty.
So how will I understand my duty. It is actually quite easy. If you are a student , your primary duty is to study. Not to think about exams, whether you will pass or fail. But are you studying
If you are a child your duty is to respect elders. I clearly say respect, not obey. Because if you obey you might end up obeying their wrong things also. But respect gives you a way to put your POV to an elder if he or she is going wrong.
Similarly with respect to each role we have to understand the duties associated with it. If we understand the duties , do it properly right will come to you. You need not have to fight for it.
We are fighting for rights either because we didn't do our duty or we were obeying someone or something blindly.
So to come out of this vicious cycle the only way is to understand duty with respect to your role.