I really never understood the sister relationship. I grew up as the only daughter and only granddaughter on both sides of my family. But in the past 21 years I have had a crash course in what it means to be a sister through my four girls.
I have learned that sisters can be very similar and still very different. No matter how many times this one may borrow that one’s sweater, she will never know when it was ok to take it without asking. I have learned they may fight with you at home but anyone else will have to deal with them first hand if they speak poorly about you.
I have learned that even the best of sisters try hard not to compare themselves to each other, but often fall into this trap anyway.
Consider the story of Mary and Martha. In the Church we have often compared these sisters to ourselves and others.