Why does crispin have to swear an oath to serve bear?

Crispin swears an oath to serve Bear as a means of survival and protection. After fleeing from his oppressive life and the threats against him, he finds in Bear a mentor and ally who offers him safety and guidance. This oath also symbolizes Crispin's journey toward autonomy and self-discovery, as he learns to trust and commit to someone who values him. Ultimately, it marks a turning point in Crispin's life, allowing him to escape his past and embrace a new path.