In the story, Frederick Douglass needed to spend more than three days washing into a creek before he decided to leave for Baltimore. And the reason for this is that Mrs. Lucretia incited him to do it and told him that it was necessary that he had to clean himself up.
"Lena" is the subject, the person performing the action. "Tell" is the verb, the action performed. "The truth" is the direct object, the recipient of the action. "Him" is affected by the action.
