BFF=Sisters

After school yesterday, we stopped at the park on the way home.  A little girl about Kota's age was there playing and the girls instantly befriended her.
After a few minutes of girl talk and tag, I overheard this little bit:

Dakota:  (talking to her new friend) You are going to be my new best friend.
Charly:  Momma says sisters are our best friends.
Dakota:  That means you are my new sister.

A little background:
When the girls fight, I tell them that their sisters are their best friends.  They will always be there for them and they will always love them.  So they shouldn't treat each other badly.  They should treat their sisters how they treat their non-family friends.
What did the girls glean from this?
If you are a sister, you are a best friend.  If you are a best friend, you are a sister.

I love how little minds work!