The crew of Supernatural loves to echo past events using imagery and dialogue, sometimes obvious, sometimes subtle. They're mile markers along the journey that encourage the audience to look back and see how far the show has come. Here's a few that I've noticed;
Pilot: The obvious mirror image of Mary and Jess both pinned to the ceiling.
Pilot: John hands baby Sammy to Dean and says "Take your brother outside as fast as you can. Don't look back."
Home: Sam says to Sari "Take your brother outside as fast as you can and don't look back." [both events happened in the same house]