The title is taken from Yoda's comment in
The Phantom Menace (talking to Mace Windu, referring to the Sith): "Always two there are, no more, no less, a master and an apprentice" [2:07:59].
0:31 - Zeb (to Rex, about their Dejarik game): "Maybe I let you win, old guy." This may be intended as a reference to what C-3PO tells R2-D2 while he's playing Dejarik with Chewbacca in A New Hope: "I suggest a new strategy, R2: let the Wookiee win" [1:00:28].
5:27 - Imperial officer: "Agent Kallus, I may have something. A power surge at a decomissioned medical station in sector eleven. Could be rebels."
Kallus: "Could be anything, a malfunction or even scavengers."
Fifth Brother: "No, I sense those we seek."
This conversation is similar to one in The Empire Strikes Back [20:29]:
Captain Piett: "Admiral?"
Admiral Ozzel: "Yes, Captain?"
Piett: "I think we've got something, sir. The report is only a fragment from a probe droid in the Hoth system, but it's the best lead we've had."
Ozzel: "We have thousands of probe droids searching the galaxy. I want proof, not leads!"
Piett: "The visuals indicate life readings."
Ozzel: "It could mean anything. If we followed up every lead, we could-"
Piett: "But, sir, the Hoth system is supposed to be devoid of human lifeforms."
Darth Vader: "You found something?"
Piett: "Yes, my lord."
Vader (upon seeing the rebels' shield generator): "That's it; the rebels are there."
Ozzel: "My lord, there are so many uncharted settlements. It could be smugglers; it could be-"
Vader: "That is the system, and I'm sure Skywalker is with them. Set your course for the Hoth system."
6:59 - Zeb (after Ezra asserts that he'll find the medical supplies first): "Cocky kid!" This seems meant to resemble Han's comment to Luke in A New Hope, after he destroys one of the Empire's sentry ships: "Great, kid! Don't get cocky." [1:35:27].
10:21 - Ezra (upon running into the Fifth Brother): "Not who we're looking for." Obi-Wan, influencing a stormtrooper through the Force, uses the same expression in A New Hope: "These aren't the droids you're looking for" [43:40]
11:13 - Seventh Sister (to the Fifth Brother): "We will use the boy as bait to draw in the others." Obi-Wan uses the same expression in Attack of the Clones (speaking to Anakin, referring to Padmé): "You're using her as bait" [11:22].
16:01 & 16:05 - Zeb (to Chopper): "I need your help." Queen Amidala says the same thing to Jar Jar in The Phantom Menace ("I need your help" [1:37:55]); Obi-Wan to Padmé in Revenge of the Sith ("Padmé, I need your help" [1:38:44]); and Obi-Wan to Luke in A New Hope ("I need your help, Luke. She [Leia] needs your help." [36:03]).
21:14 - Kanan: "We really have no idea what we're up against." Luke uses the same expression shortly before the Battle of Yavin in A New Hope when he tells Han, "You know what's about to happen, what they're up against" [1:41:48].