This is ὑμῶν, the genitive plural form of the second person pronoun, meaning 'of you' or 'your' when addressing groups. Greek used the genitive case for possession rather than separate possessive adjectives for all persons. This form appeared constantly in epistolary literature: 'your faith,' 'your love,' 'your work.' It allowed apostles to speak about the collective characteristics, possessions, or responsibilities of communities. The form could also indicate source ('from you') or relationship ('your brothers'). In New Testament ethical instruction, 'your' marked both what believers possessed in Christ and what they were responsible to demonstrate in conduct and character.