Abraham is not an aesthetic hero, since aesthetics demands that he remain silent in order to save someone. In fact, his silence is not meant to save Isaac, but is rather a way of concealing his intention to kill Isaac. Nor is Abraham a tragic hero, since the ethical would demand disclosure. Since he is neither an aesthetic hero nor a tragic hero, Abraham is either higher than the ethical or he is lost.
Unlike the tragic hero, Abraham cannot speak and cannot be understood. At any moment he can stop it all and speak, but then his ordeal becomes merely a spiritual trial. There is no way he can explain that the ethical itself is his temptation, nor can he explain the movement of faith. Who would understand that he is planning to kill Isaac, but that he has faith that he will get Isaac back by virtue of the absurd?
Genesis attributes only one speech to Abraham on the journey to Mount Moriah. Isaac asks his father why he has no burnt offering, and Abraham simply replies: "God himself will provide the lamb for the burnt offering, my son." These words prompt Johannes to launch a discussion of the value of last words. He suggests that a tragic hero whose heroism lies in action does not need last words: it's unnecessary chatter that distracts from his actions. The intellectual tragic hero on the other hand needs last words: these words are the culmination of his life, the words that make him immortal.
Abraham and the intellectual tragic hero share in common their orientation toward the spirit. As the father of faith, Abraham needs to say something. On the other hand, according to the paradox, Abraham cannot speak. If Abraham were to answer Isaac with the truth, that Isaac is to be the sacrifice, he would be giving up everything. If he were to tell Isaac at all he should have done so long before. To say "I don't know" would be a lie, and dishonest. His answer, however, is not a lie, nor is it disclosure. Abraham employs irony, the tool that allows one both to say something and to say nothing. Abraham's answer is not a lie, since, by virtue of the absurd, it is possible that God will provide a lamb, but at the same time, Abraham has made the movement of resignation and he fully intends to sacrifice Isaac. Abraham speaks, but his speech is not understood.
One last time, Johannes reasserts that either Abraham is the father of faith and stands above the ethical in an absolute relation to the absolute that cannot be communicated, or else Abraham is lost.
In the epilogue, Johannes returns once more to the assertion that faith is not enough, that we must go further. He suggests that no generation learns the essentially human from the previous generation: it is something it must learn on its own. He suggests that the essentially human is passion, and that with passion we all must begin primitively: we cannot learn love from the previous generation, pick up where they left off, and go further. The highest passion of all is faith, and with regard to faith we all begin at the same place, and no one can go further than faith.
Heraclitus asserted that no one can step into the same river twice. Zeno, his disciple, wanting to go further, asserted that no one can step into the same river even once. In trying to go further, Zeno and the Eleatics denied motion and set themselves back to what Heraclitus had abandoned.
The main point of Problema III is that, though the ethical calls for disclosure, Abraham could not speak. While it may not be "ethically defensible" for Abraham to conceal his undertaking, Abraham's relation to God brings him above the ethical. God's command to Abraham is unique to Abraham and is made only to Abraham, and so Abraham enters into a private relationship with God. As a result, this command isolates Abraham from the universal. Because the command is unique and private, it cannot be transmitted to other people in an understandable manner. How can Abraham explain to others that the ethical is his temptation: "I am suffering great anxiety because I am faced with the constant temptation to do what I, and everyone else, knows to be right"?
It may help to understand Abraham's paradox if we look at his story not from his perspective, but from someone else's. Suppose I were to meet Abraham on the street: if he were to tell me God had told him to kill his only son, I would think he was crazy. There is no proof of any kind that Abraham can produce to convince me that killing Isaac is indeed God's will. The command came privately to Abraham, and it cannot be shared or explained to anyone else. Further, if Abraham were to share his ordeal, it would no longer be a private ordeal that he shares with God. He would be making it public and would thus be creating a gulf between himself and God.
Therein lies the difficulty of Abraham's words to Isaac. In asking a question, Isaac calls for Abraham to speak, but Abraham cannot possibly tell the direct truth without breaking his covenant with God. While Abraham does not lie, he speaks in a way that cannot be understood. God will provide a lamb for the burnt offering only by virtue of the absurd, and so those words can only be understood by Abraham himself, who has made the leap of faith into the absurd. Abraham speaks the truth, but a truth that only he can understand. Irony and paradox both deal with contradiction, so it is only fitting that irony should be the only suitable manner of speech that can express the paradox.
The epilogue returns once more to the theme of the preface: everyone wants to move beyond faith, thinking that it is easily achieved. Hegel has a grand theory of history, according to which everything slowly progresses toward a final, utopic, synthesis. We build upon the knowledge and experiences of past generations until we arrive at the truth. For instance, Einstein's relativity could not have been discovered before the formulation of Maxwell's equations or Newton's laws. Einstein may have been brilliant, but he was still building upon past discoveries.
Johannes suggests that faith is not like science: we cannot pick up where the previous generation left off. Faith, like love, is a kind of passion, and we cannot pick up passion by proxy. The value of faith lies not in reflecting upon it disinterestedly, but in throwing oneself passionately into it. Faith must be experienced, not just intellectualized.
The closing reference to Heraclitus and Zeno compounds this point. Heraclitus is famous for saying that everything is fire, and that everything is constantly changing. One of his examples of this perpetual change is that one can never step into the same river twice: the actual water that makes up the river is constantly moving, and is constantly different. Zeno is famous for the paradox that bears his name, which can be formulated in a number of different ways. One method is to point out that to get to a certain point, one must first go half the distance to that point, and before that one must go half the distance to that halfway point, and so on. Because there is always a shorter, halfway distance between one's present location and one's destination, it is impossible to move at all. Thus, Zeno concludes, contrary to Heraclitus, that there is no change at all: motion is an illusion.
Heraclitus formulated his doctrine in response to earlier theories that tried to explain the universe in terms of certain static forces or elements. Heraclitus saw a dynamic universe, which he expressed vividly in his claim that everything is fire. Zeno took Heraclitus' perpetual change as a starting point, and tried to go further, ultimately concluding that change does not exist. Zeno, like the Hegelians, only understood his predecessor in a distanced, reflective manner. If he had had the passion truly to understand Heraclitus' point of view, perhaps he would have felt no need to move beyond it.