The opening quote and loose plot come from Aesop's fable "The Wolf in Sheep's Clothing".
First use of the term "kehrseite" and the associated "kehrseite-schlich-kennen." "Kehrseite" comes from the German meaning "back, reverse, the other side," essentially "the ones that aren't wesen," while "kehrseite-schlich-kennen" likely comes from the combination of the above and a variant on the phrase "alle Schliche kennen" meaning "to know all the tricks."
First appearance in the show of a mixed-wesen relationship other than Monroe and Rosalee.
"Seelengut" comes from the German word "seelen," meaning "souls," and "gut," meaning "good."
Second use of the distinctive First Presbyterian Church of Portland for a location. It can be identified by it's unique stained glass and carved wood interiors. It was first used as an interior for a retirement home in Tarantella, Season 1, episode 11. In this episode we see the ornate sanctuary when the pastor is meeting with his leaders to calm them after their financial crisis.