I cannot give you the whole answer but here are some points..
This play is related to the social issues of the British society. Major Barbara was written in 1905. at that time, Europe was divided in to two major camps 1. those favoring wars and 2. those opposed to it.
In the play, Shaw draws into question the validity of religious and charitable organizations, such as the Salvation Army.He also ridicules the superficial family ties of the rich where nothing is sacred except money.
The play also tells us about the 19th century through capitalism and industralization and exploitation of the female workers by large industrialists at that time and it is observed that the girls of the Salvation army were judged as hypocritical
exploitation, horrible working conditions, low wages were common at that time and the exploited and laid off workers comes into the Salvation Army shelter where Barbara treats them with milk and bread which is meager food for them.
you can also explain how she saves jenny from Bill walker, and how she had always refused to take money from people who make money through what she considered morally wrong method and in teh end the young women comes to terms with the real wrold in which she lives and acknowledges that the basic needs of man, such as food and clothing need to be met before a man's soul is saved.
her rebel again traditional feminine role deals with the concept of growth and development and tells us that Barbara has matured and yet is still in some ways a child...
I meant novelguide.com. Sorry my mind was straying away from the topic. The website is below.
I don't know. check eNotes study guides for Major Barbara. Maybe that will help.