Bobby tells Jack, "As a wise man once said, it ain't how hard ya hit, it's how hard you can get hit and keep moving forward." Jack assumes the motivational affirmation is a Gandhi quote, but it is actually a line Rocky Balboa (from the Rocky series) says. The actual movie of the quote is Rocky Balboa (2006).
Sam says an unreliable witness in Atlanta had taken one-too-many hits of the brown acid. At the Woodstock Festival in 1969 a DJ named Wavy Gravy went onstage and warned folks that the brown acid (homemade LSD on brown blotter paper) being sold was contaminated and causing bad trips.
"Stranger in a strange land" is a phrase from the King James Bible (Exodus 2:22): "And she bore him a son, and he called his name Gershom: for he said, I have been a stranger in a strange land." (Also translated as, "a sojourner/traveler/alien in a foreign land."
Maggie is seen removing a Rawhead tooth from an injured hunter. This is only the second time the monster "Rawhead" is mentioned. The first time is in Faith (Season 1, Episode 12) when Dean is electrocuted killing one.