I exact no promises and impose no obligations on you.
I recognize no obligations toward men except one: to respect their freedom and to take no part in a slave society.
His moral obligation is to do what he wishes, provided his wish does not depend primarily upon other men.
He thought that she owed him nothing, or every kind of anger and scorn she could command; and yet there was a human obligation she still had toward him: she owed him an evidence of strain in this meeting.
There are no more uses of "obligation" in the book.