King was a minister criticized by clergymen, so he tried to justify his cause by paraphrasing the words of Thomas Aquinas, a notable interpreter of God's order on earth. He uses this allusion because he wants to underline the crucial difference between just and unjust law, that has been confirmed by one of the highest intellectual authorities in the fields of philosophy and religion. King provides a religious justification for the concept of nonviolent resistance.
Its internal because she is doubting that the drought will work or not, her dilemma is that she thinks that the potion that will make her appear dead will either not work or actually kill her.