The title is the Old Witch but the story is more about two sisters who go two different paths. It reminds me slightly of the Rose Red & Snow White story but here the sisters are not close (apparently).
One sister goes off and is nice to everyone. When she runs into trouble with the witch, the help she once gave to others is returned to her. Her sister follows the same path, but is not nice to those along her path, so when she runs into the same trouble, she does not get any help. The moral (as fairy tales and fables commonly have) is that you must be nice to others to get niceness in return.
(image from google)
However, I would like to note that the girls in the story, while painted to be good (well, the first sister anyway), the trouble with the witch comes when they STEAL from her. So It’s hard to say what the real lesson is. Be nice to others and when you steal from someone, they will help you? I don’t know. Any thoughts?