Answer:
He feels strongly about preserving and maintaining them.
Step-by-step explanation:
In this excerpt, Joseph is willing to continue whith his tribe's cultural tradition: to regain their lands from the hands of the white. Joseph's father has just died without being able to regain his land in Oregon. As a consequence, Joseph feels stronger in preserving and maintainnig their resistance against the white. "He left a good name on earth. He advised me well for my people" these words make Joseph's intentions clear: he will go on with the tribe's peaceful fight against the white.