"You never really understand a person until you consider things from his/her point of view... until you climb into their skin and walk around in...

This quote comes in Chapter Three after Scout's day at
school which, from her perspective, went so terribly. She begs Atticus to be taught at
home by him so she won't have to go back, and the quote you have highlighted is the
response that she is given by him. In a sense of course, the quote stands for a much
bigger theme in the novel which points towards the way that this novel is a
coming-of-age story. Through it we see how Scout and Jem are both forced to grow up
through the events and conflicts that they witness and are involved in, and how they
both learn to metaphorically "climb in the skin" of those around them and walk in their
shoes.

Of course, Atticus is definitely right. It is so
easy for us to judge and criticise others, but we need to remember that we do not always
know the full picture, and to a certain extent we can never fully understand the
different pressures and perspectives that others are facing and how these pressures
impact them. Atticus gives Scout an excellent piece of advice that cautions us to not be
too quick with our judgement until we have taken time to truly understand somebody else
and their situation that we may not be aware of.