American citizens have many rights, including freedom of worship, freedom of expression, and the right to a trial by jury. Along with these rights go certain responsibilities, including supporting and defending the Constitution, serving for jury duty when requested, and obeying and respecting the law.
noun: responsibility the state or fact of having a duty to deal with something or of having control over someone. the state or fact of being accountable or to blame for something the opportunity or ability to act independently and make decisions without authorization. a thing that one is required to do as part of a job, role, or legal obligation. a moral obligation to behave correctly toward or in respect of.
Why does Okonkwo act as he does despite the advice of others not to participate in the killing of Ikemefuna?
It is a duty because you have to do it. I would say that in the abstract you have a responsibility to serve on juries in order to see justice done. If you are actually called as part of a jury pool and are selected to serve, it then becomes a duty in that it is now compulsory for you to serve (barring being excused for a good cause).