Read this excerpt from incidents in the life of a slave girl by harriet ann jacobs: o, ye happy women, whose purity has been sheltered from childhood, who have been free to choose the objects of your affection, whose homes are protected by law, do not judge the poor desolate slave girl too severely! if slavery had been abolished, i, also, could have married the man of my choice; i could have had a home shielded by the laws; and i should have been spared the painful task of confessing what i am now about to relate; but all my prospects had been blighted by slavery. i wanted to keep myself pure; and, under the most adverse circumstances, i tried hard to preserve my self-respect; but i was struggling alone in the powerful grasp of the demon slavery; and the monster proved too strong for me. what is the purpose of comparing the circumstances of slave women and free women in this excerpt

It draws a parallel between a slave and a free woman to emphasize the disparities faced by the slave women.  

Explanation:

Harriet Ann Jacobs' "Incidents In The Life of A Slave Girl" is an autobiographical work detailing the earlier life and suffering that slaves, especially women had to face. With the pseudonym of Linda Brent, Jacobs gave a first person narrative voice to the whole story.

The given passage is from Chapter X of the book titled "A Perilous Passage In The Slave Girl's Life" where she gives her reasons for doing what she thinks is best for herself. She drew a parallel between the women, slaves and free and their differing situational circumstances that made her do what might be considered wrong for any woman. It also shows her envy of the free women who can chose their husbands and do whatever they want. But considering her situation, she can do none of her planned ideas as she has to first make herself safe, thus ignoring what is right or wrong.