Adam and Eve
Adam and Eve were two of God's most prized creations, whom he gave refuge to in the Garden of Eden. After Lucifer's corruption of Lilith, God banished Adam, Eve and all of mankind from the Garden. Some time after their banishment, Eve would give birth to Cain and later Abel, and give rise to a bloodline that would reach all the way to Sam and Dean Winchester.
Drinking tea together in the Bunker library, Rowena regales Chuck with stories of when Crowley / Fergus was a child and would run around their village naked. Reminding Chuck that Adam and Eve were the same way.
When Jack consumes the Occultum and finds himself in a strange wooded area. He is greeted by a young girl who tells him he is in the Garden. Asking if she means like Adam and Eve, the Girl tells him how they were God's most prized creations before He banished them and mankind from the Garden.