Who is The Van Wageners from Narrative of Sojourner Truth and what is their importance?

The Van Wageners were the couple that took Isabella and her son in when they left the Dumont land. Isabella was determined to make Dumont honor his promise to free her a year early. When Dumont came to Wagener's home to take Isabella, Van Wagener gave him $25 for both Isabella and Peter to allow them to remain. Van Wagener told Isabella not to call him master, and when she finally left the Van Wageners home, she took their last name.