Abraham's call to murder
Abraham is a figure of holiness and righteousness in human history, but in this story, he gets it in his head that God wants him to commit a heinous act of true betrayal and evil. By killing his son, he obviously forsakes the principles of nature, and therefore, the story is existentially ironic. Carl Jung is famous for noticing the perplexing nature of ancient mythology; in this story, God's behavior with his prophet and the prophet's blind obedience of his conception of God is quite unnerving, frankly, but by the end of the story, Abraham is firmly established in a new religious cult without human sacrifice, which is certainly an important step forward in human history. The outcome of God's call to murder is perfectly ironic because the story ends in peace and mercy.
The pagan underpinning
By taking the famous Bible story and setting it in a stage production, the author allows the audience a chance to reassess the story of the Western faith. The story is surprisingly influenced by paganism, which sometimes feels so far from English Christianity (the play was written in England in Medieval times). The irony of Abraham's story is that it is essentially a modified version of paganism. For instance, the story is strikingly similar to cults in Mexico who used to slay children at the top of their pyramids. For a second, the story looks like it is going to be one of those situations.
Isaac's acceptance
Isaac is a hero in his own right because the dramatic irony of his pending death is revealed to him. What does Abraham have to accept? He has to accept bitter powerlessness against fate, plagued by the only source of true hope to do something that will leave him hopeless and sorrowful. But that's nothing compared to what Isaac accepts; Isaac accepts that if his father's belief is that God truly wants his father to murder him in a ritual child sacrifice, then it is his fate to accept that death. Isaac's ironic and stunning act of obedience and faith is a commentary on the story's inherent Messianic flavor, which is obviously something which the seemingly-Christian playwright would not have overlooked.
The irony of salvation
The dramatic tension of the story is that everything seems perfectly doomed until miraculous, the hand of God intervenes at just the right moment for true artistic climax, and then, the story evolves suddenly. One minute, the story is a harrowing uphill journey toward death and sorrow, and the next minute, the story is a mountain-top bliss where the cast is made certain that God intends to bless them through fate, not curse them. The dramatic irony of the play is therefore divine salvation. In literature, this is often called "deus ex machina."
The doctor's ironic advice
The play ends on an ironic note when a official doctor comes onto the stage to analyze the contents of the play, lest anyone misunderstand the strangely dense narrative portrayed. The doctor has ironic advice to offer. Instead of hoping that God will spare us from suffering, the doctor tells the audience to accept suffering and death as the divine call on human life to trust the universe's creator in all things. That is literally an urge to fully accept the dramatic irony of life and death, because God symbolically represents a cosmic order which humans do not comprehend in our finite animal points of view. The doctor's painful advice can be rephrased this way: "Everything happens for a reason. Accept your fate."
