I do believe that Maud Martha is justified in sparing the mouse as told in the poem "Maud Martha Spares the Mouse" by Gwendolyn Brooks.
I find that Maud Martha is justified given that she allows her heart to make the decision to release the mouse from the trap. Maud Martha thinks about the mouse, not as a destructive creature, but as the leader of a family. She, herself, can relate to the idea- she is a leader of her family. She worries for the mouse's family in the same way that she would worry about her own if she were not there to support them.
This poems is a wonderful example of putting yourself in another's shoes. It is no longer aboutthe past actions of the mouse:
eluding her, the tricks, the clever hide-and-go-seeks, the routes it had in all sobriety devised, together with the delicious moments it had, undoubetdly, laughed up its sleeve.
Instead, the mouse has transformed in the eyes of Maud Martha. She personifies the mouse- gives its children names, gives it a spouse.
By doing this, Maud Martha creates a relationship with the mouse. She finds herself wanting to care for it. By doing so, Maud Martha has changed, not only her mind, but her soul.
A life had blundered its way into her power and it had been hers to preserve or destroy. she had not destroyed. In the center of that simple restraint was–creation. She had created a piece of life. It was wonderful.