Explain the terms of the covenant (agreement) between dog and man.

From the text:

This was the ancient covenant that the first wolf that came in from the Wild entered into with man.  And, like all succeeding wolves and wild dogs that had done likewise, White Fang worked the covenant out for himself.  The terms were simple.  For the possession of a flesh-and-blood god, he exchanged his own liberty.  Food and fire, protection and companionship, were some of the things he received from the god.  In return, he guarded the god’s property, defended his body, worked for him, and obeyed him.