Perhaps you should have put this in "homework help." I wonder, did you even read "Civil Disobedience?" And do you have classroom definitions of ethos, pathos, and logos? Because they are all Latin (actually, I think latinized Greek to some extent), and have rather specific meanings. You should know them from there English root derivations: Ethics, pathetic or actually pathos itself in the theater; and logos, word or the word. Or The Word, as in the Bible, in the case of Thoreau, possibly. It's been a great many years since I read Civil Disobedience.
The ethics, of course, is the point to the whole essay: that civil disobedience is not only a right, but a duty, in opposing injustice. If people were to let "I could be arrested" interfere with them making their moral point, Thoreau might privately consider them cowards, however gentle he might be in public. He felt it was his duty to go to jail rather than submit to injustice. I feel he was right. But it may be a luxury only those who do not leave a starving family behind can afford. Woodstock made much of the "martyrdom" of Joan Baez's husband in prison, organizing hunger strikes and all the rest. But his wife made enough money that he could afford to take that kind of time away. He could sacrifice his own freedom because they would be fine without him for the time involved. Civil disobedience is a tough thing when the whole family is brought down in the fight.
Perhaps that gives you the pathos, eh?
And the whole thing is logos: the Word. The significance of the pen which is indeed mightier than the sword.