This verse is a simple question posed by Tobit to Azariah (who is actually the angel Raphael in disguise) shortly after Tobit has hired him to accompany his son Tobias on a journey.

Here's a breakdown of what it means:

"And Tobit said to him...": This introduces the speaker (Tobit) and the recipient of his words (Azariah).
"Brother...": This is a polite and respectful way to address a stranger, implying friendliness and equality.
"...of what tribe and of what family are you? Tell me.": This is the core of the verse. Tobit wants to know Azariah's lineage and social standing. Why is he asking?
Trust and Reliability: Knowing someone's tribe and family was a way to establish their background and trustworthiness. In that society, family reputation mattered a great deal. If Azariah came from a reputable family, Tobit would feel more comfortable entrusting him with his son and a large sum of money.
Social Norms: Asking about someone's lineage was common in that culture. It helped to place them within the social structure and understand their potential obligations and loyalties.
Ensuring a Good Match: Tobit might have been thinking about more than just the journey. He might have been considering Azariah as a potential future contact or even son-in-law. Knowing his family would be crucial for that.

In short, Tobit is trying to ascertain Azariah's background and trustworthiness by asking about his tribe and family. It's a standard social inquiry of the time, aimed at establishing a basis for trust and ensuring a safe journey for Tobias. Of course, Tobit doesn't realize he's talking to an angel, so he's applying earthly standards to a heavenly being.