Why does Kevin say it is ok to break a promise when you are on a quest?

n chapter 11, Kevin (also known as Freak) explains to Max that "it's okay to break a promise if you're on a quest." He tells him this because Max has promised his grandmother that he won't go to a certain place, called the Testaments, but Kevin and Max have found a purse that belongs to a woman who lives there, and Kevin says that they should go on a quest to return the purse because there might be a reward in it for them.

Explanation: since i helped can i have brainlist please that would be great;y appericated :D

i love cake

and don't hate

i know i'm fat

but what's wrong with that

i cant rap

but im sure ya know that

its just for fun

so quit hatin' son

~courtney

what he !