The words that Jace and Alec are saying when they becomes parabatai is from the book of Ruth in the Bible. With the exception that "Lord" is changed to "Angel" to better fit the shadowhunter story.
Luke said the words "Beati bellicosi" while laying Gretel to rest. "Beati bellicosi" in the books is the motto of the Praetor Lupus.
Both of the young actors who portrayed younger versions of Jace in this episode were given contacts to match Dominic's different-colored (brown and half-blue) eyes.
Jace was originally going to be hiding out in a college in this episode.
The scene featuring Elaine, Simon, and Raphael was shot in the Goodlake restaurant in Ontario.