Note: the translation of your poem may vary, so check the word choices before answering.
In the first stanza, the personification of hatred creates an image of a predator, a creature able to "vault" obstacles. Words like "vault," "pounce" and "track" add to this image. (Your translation might have "regards," "leaps," and "overtakes" -- but the idea is the same).
Personification is used later in the poem to contrast hatred with compassion, brotherhood, and doubt. Hatred, she writes "never tires" of being an executioner. Furthermore, it's "always ready," even if it must wait. In this way, he can wait for compassion and brotherhood to give way to violence.
Brotherhood, compassion (or empathy, depending on the translation) and doubt, she says, are "sluggish" and do not compel people to act in the way hatred does.
The effect of the plague that the narrator in “The Decameron” describes as “even worse, and almost incredible” as he tries to convey the horror of that time period is: Parents refused to care for their dying children.
Fathers and mothers refused to assist and care for their own children, it was as if their children did not belong to them.
