This is the second episode about Mary's friends getting married. The first one was "Dear Wife," season 4, episode 39 (the last episode of season 4).
Mrs. Haversham: Donna, let me ask you something; when your time comes, with Mary that is, will you do exactly as your preach?
Mrs. Stone: Pause and a nervous Eh. No.Mrs. Stone and Mrs. Haversham Laugh and hug each other