Love is more powerful than anything
The idea that nothing is more powerful than love becomes a motif from the first letter sent by Abelard. Love gives Abelard the power to endure hardships and humiliations just to be with the person he loves the most and Abelard lets himself be guided by his feelings. Love produces a drastic change in Abelard who becomes a completely different man: he abandons his studies and his desire to acquire more knowledge is replaced by his desire to please Heloise and to be with her.
Marriage
For Heloise, marriage is not something that she desires. Heloise tells Abelard that she sees marriage as a symbol for confinement, a prison that will trap both her and Abelard who will no longer be able to progress in his studies and his career. This view is different from the way marriage was seen during Heloise and Abelard’s time, when marriage was sacred and the biggest sin was living with someone else without being married. Heloise didn’t let herself be influenced by the ideas in her time and chose instead to follow her own path.
Sin
When Heloise talks about her desire for Abelard, she admits that it is a sin. Considering the time when the letters were written and the religious background, it is no wonder that sexual desire was associated with sin and a symbol for moral degradation. Sexual desire was something that was frowned upon even when two people were married and it was considered as being something impure and thus something that should be avoided.
Death
In one of his letters, Abelard asks Heloise to make sure that he will be buried beside her, should he die sooner than she. In another letter Heloise chooses to talk about death and for her, death symbolizes pace and happiness is that means that she will be able to be with the person she loves. For Heloise and Abelard, death and the idea of afterlife is synonym with the chance of being together, both knowing really well that the possibility of meeting again in person is very slim.
Cloister
In her last letter to Abelard, Heloise admits that the only reason she agreed to go and spend the rest of her life in a cloister was because Abelard asked her to. For Heloise, the cloister she lives in is a prison, a coffin where is she forced to stay. Because Heloise is a woman who is afraid of everything that would make her feel trapped, both the institution of marriage and the cloister are seen as symbols of confinement and stagnation that leads to a symbolic death because they stop a person from growing.