The first part of this quotation is easy, it’s always easy to fight as if you are right. Most of the time most of us are convinced that we are right.
The second part, that one is harder to do. Listening as if you are wrong requires a degree of humility. That part will require self-control, and letting go of self-righteousness.
However, listening as if you are wrong seems to be essential to ensure that we fight only when it is necessary or just.