I really liked those four stories, they were a brilliant way to start the book. They show different ways in which Abraham may have reacted to God's request, and making us think about the consequences. The commentary on each section is my own interpretation, so I could well be wrong.
I.
Summary: Isaac is fearful, Abraham tries to be consoling in his attitude. Then Isaac begs for his young life, and Abraham turns on him, saying "Foolish boy, do you believe I am your father? I am an idolator. Do you believe this is God's command? No, it is my own desire." Then Isaac full of anguish cries out to God for Him to be his father since he has none on earth and Abraham whispers under his breath: "Lord in Heaven I thank Thee; it is after all better that he believe I am a monster than that he lose faith in Thee."
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-When a child is to be weaned, the mother blackens her breast, for it would be a shame were the breast to look pleasing when the child is not to have it. So the child believes that the breast has changed but the mother is the same, her look loving and tender as ever. Lucky the one that needed no more terrible means to wean a child!-
Here, Kierkegaard confronts the notion that Isaac would lose all faith in God because God had asked that he be killed by his own father. So perhaps Abraham should turn on him as he did in this version, since how could Isaac be the father of a nation if he had lost God? The weaning of the child metaphor is brilliant - the child is attached to the breast, not the mother, so you blacken the breast to show that it is the mother and not the breast that the child should be attached to. As with Isaac - it is not Abraham, but God that Isaac should be attached to. But what a terrible way to wean him!
But K. would say this is a misunderstanding of the story, because Isaac does not need to believe that it was Abraham and not God that wanted to kill him.
II.
Summary: Abraham does as he is commanded, but silently, joylessly, with despair. His gaze lingers on the ground, when he sees the mountains of Moriah his looks away. He prepares to kill Isaac, accepted the ram, and all was well - yet Abraham became old, he could not forget what God had demanded of him, he saw joy no more.
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-When the child has grown and is to be weaned the mother virginally covers her breast, so the child no more has a mother. Lucky the child that lost its mother in no other way!-
Here, we have the Abraham of resignation. He does what God wishes, resigns himself to the will of God, but does not have faith that God will give him Isaac back again. He does not have faith that God will help him in this life, only in the next. But when the mother covers her breast, is she less of a mother? If your mother asks you to do something evil, don't you assume to the end that the act is not evil and you've misunderstood it?
III.
When Abraham gets to Moriah, he throws himself down in front of God and begs forgiveness for having been willing to sacrifice his son, to have abandoned his sacred duty to him. He couldn't understand why it was a sin to want to sacrifice the best he owned, but if it was a sin, why was he forgiven, for what crime could be more terrible?
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-When the child is to be weaned the mother too is not without sorrow, that she and the child grow more and more apart; that the child which first lay beneath her heart, yet later rested at her breast, should no longer be so close. Thus together they suffer theis brief sorrow. Lucky the one who kept the child so close and had no need to sorrow more!-
Basically: is your loyalty to God, or to worldy morality? Do you reject the will of God for jumping to the conclusion that they are not compatible? Does your maturing and independence really need to distance yourself from your mother? (I'm a bit unsure of this one.)
IV.
Summary: The story plays out as per the story, except that when Abraham is about to perform the sacrifice, Isaac notices a shudder run through Abraham, and than his hand was clenched in anguish. They return home, but Isaac had lost his faith, although Isaac never told anyone and Abraham didn't realize this.
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-When the child is to be weaned the mother has more solid food at hand, so that the child will not perish. Lucky the one who has more solid food at hand!-
Abraham does not have faith, and Isaac sees this, and consequently loses faith himself - why would his own father kill him if he wasn't sure he'd get him back? The child has faith that although he is not to be given the breast any more, he will be provided for. He would lose faith in his mother if he thought that she did not.
I think these are beautiful ways of portraying different ways of thinking about the story. There is so much depth to be found in it - it's not just about a religious fanatic, necessarily.