Provide a short summary of the reasons Darcy provides for refusing to support Wickham in his quest for becoming a parish rector/

Darcy insists he did carry out his father's wishes by giving Wickham the inheritance. Wickham instead squandered the money and returned asking for more. When Darcy refused Wickham apparently tried to seduce Darcy's 15 year old sister! These are pretty good reasons not to support Wickham in his quest to become parish rector.