Scribbled on Carrie's notebook, seen during her Congressional hearing, are the words "You killed my son - prepare to die." This echoes the famous line "You killed my father - prepare to die!" uttered by Mandy Patinkin
in the film The Princess Bride (1987). Patinkin plays one of the lead roles on Homeland.
At around 19:30 they talk about a bombing on Buenos Aires, Argentina at a Jewish Comunity Center. That really happened on July 18th, 1994.
Quinn's code name is Red 5, the same as Luke Skywalker in A New Hope.
Morena Baccarin (Jessica Brody) has the beginning of a baby bump (her son with first husband, Austin Chick) that she continues to hide throughout this season.
David Portillo, the majority counsel asking questions of Carrie Mathison, wears a lapel pin identifying him as a member of Congress. These are worn by congressmen so as to readily identify them to Capitol Police and other staff. As a staff attorney, he is not a member and should not be wearing the pin.