The Clone Wars - S5E2 - "A War on Two Fronts"

12:13 - Obi-Wan (to Steela):  "Be mindful of your frustration.  It will only hold you back."  In Attack of the Clones, he uses the same expression:  "Be mindful of your thoughts, Anakin; they betray you" [12:29].

14:55 - Anakin (after Steela shoots a target):  "Impressive.  Most impressive."  Vader gives the same compliment to Luke in The Empire Strikes Back [1:44:30].

16:21 - Obi-Wan (to Anakin, about the rebels):  "We can only protect them; we cannot fight this war for them."  This echoes what Qui-Gon says to Queen Amidala in The Phantom Menace:  "And I can only protect you; I can't fight a war for you" [1:37:45].

16:29 - Obi-Wan (about the droids):  "There are too many."  Captain Panaka says something similar in The Phantom Menace (referring to battle droids):  "There are too many of them" [23:25], as does a Jedi youngling in Revenge of the Sith (referring to the clones executing Order 66 at the Jedi temple):  "Master Skywalker, there are too many of them" [1:23:40], and a rebel pilot says basically the same thing in Return of the Jedi (referring to TIE fighters):  "There's too many of them" [1:35:13].

17:10 - Obi-Wan (to Steela, referring to a droid tank):  "We'll handle this."  Qui-Gon (referring to himself and Obi-Wan) also says this when Darth Maul appears in The Phantom Menace [1:50:29], although Obi-Wan also says something similar in Attack of the Clones (about fighting Count Dooku):  "Anakin and I can handle this" [2:03:07].

19:41 - Battle droid (to the rebel convoy):  "Halt!"  In The Phantom Menace, a battle droid also says this to Qui-Gon as he leads a group of Naboo to a ship [24:25].

21:11 - Lux Bontari:  "Good luck."  It's ambiguous whether he directs this to Steela or Ahsoka, but in The Empire Strikes Back, an unidentified Rebel pilot wishes Luke good luck [36:02] and Luke wishes Lando good luck [2:00:09], and in Return of the Jedi, Han and Lando wish each other good luck [Han to Lando at 50:33 and Lando to Han at 52:21].

The Clone Wars - S5E1 - "Revival"

2:37 - Maul (to Savage):  "Always two there are, my brother, a master and an apprentice."  Speaking to Mace Windu, Yoda says almost the same thing in The Phantom Menace:  "Always two there are, no more, no less, a master and an apprentice" [2:07:59].

3:12 - Maul (to Savage):  "And I shall complete your training, not as your brother but as your master."  Vader uses the same expression in The Empire Strikes Back when he tells Luke, "Join me, and I will complete your training" [1:50:39], and the Emperor uses it in Return of the Jedi (also speaking to Luke):  "I am looking forward to completing your training" [1:31:04].

7:20 - Maul:  "Hondo's base will soon be ours, and he will not survive this."  Near the beginning of The Phantom Menace, Rune Haako says something similar as the Jedi cut down battle droids:  "We will not survive this" [6:12].  There's also some resemblance to what Palpatine says to Luke in Return of the Jedi:  "And your friends on the Endor moon will not survive" [1:44:25].

14:27 - Hondo:  "Retreat!  Retreat!"  Jar Jar also yells, "Retreat!  Retreat!" in The Phantom Menace [1:56:53].

18:25 - The cockpit of Maul and Savage's ship features yet more uses of the hexagon design seen in the homestead garage in Attack of the Clones and A New Hope:

The Clone Wars - S4E22 - "Revenge"

10:25 - Mace Windu:  "This is clearly a trap."  The context here is different, but Admiral Ackbar says, "It's a trap!" in Return of the Jedi [1:35:03], and Leia says it twice in The Empire Strikes Back [1:39:50].

12:56 - Maul (to Obi-Wan):  "I have been waiting for you."  Vader greets him the same way in A New Hope:  "I've been waiting for you, Obi-Wan" [1:30:09].

17:42 - Ventress (to Obi-Wan):  "It looks like I'm here to rescue you."  Luke says the same thing to Leia in A New Hope:  "I'm here to rescue you" [1:16:09].

The Clone Wars - S4E21 - "Brothers"

12:54 - Morley (upon entering a shelter and seeing dead junkers):  "What the?"  In Attack of the Clones, an alien on Coruscant makes this same exclamation as he sees Obi-Wan flying through traffic while hanging from a droid [15:08]; Han Solo says it in A New Hope after emerging from hyperspace into a meteor shower [1:03:15], and in Return of the Jedi, a scout trooper says this after being hit by Wicket [1:05:38].

The Clone Wars - S4E20 - "Bounty"

5:21 - The control panel in the cockpit features an-other use of the hexagonal pattern seen in the homestead garage in Attack of the Clones and A New Hope:

9:51 - Dengar:  "Heads up people.  We got company."  Han Solo uses a similar expression in A New Hope:  "Luke, we're gonna have company!" [1:15:46].

11:34 - Dengar (after he falls of the subtram):  "Poodoo."  Sebulba also says this after his podracer crashes in The Phantom Menace [1:09:20].

14:19 - Major Rigosso:  "Over my dead body."  Han Solo uses this same expression in A New Hope [50:42].

The Clone Wars - S4E19 - "Massacre"

2:15 - Mother Talzin (to Ventress):  "And then you will fulfill your destiny and become a true Night Sister."  Emperor Palpatine uses the same expression in Return of the Jedi when he tells Luke, "Now fulfill your destiny, and take your father's place at my side" [1:53:38].

2:54 - Count Dooku (to Grievous):  "Go there, and wipe the witches out, all of them."  Darth Sidious uses the same expression in The Phantom Menace (talking to Nute Gunray and referring to the Gungans):  "Wipe them out, all of them" [1:44:52].

5:22 - General Grievous (to a battle droid):  "Begin landing our troops."  Darth Sidious says almost the same thing to Nute Gunray in The Phantom Menace:  "Begin landing your troops" [4:46].

16:05 - Mother Talzin:  "Pain, Count Dooku.  You will know terrible pain."  This is similar to what Yoda says to Mace Windu in Attack of the Clones:  "Young Skywalker is in pain, terrible pain" [1:21:27].

The Clone Wars - S4E18 - "Crisis on Naboo"

8:59 - Derrown (in disguise as a senate guard):  "What's your identification number?"

Senate Guard:  "SG 1984."

Derrown:  "Alright, move along, and stay sharp."

This exchange includes three bits of dialogue borrowed from A New Hope:  an Imperial officer asks Han, "What's your operating number?" [1:15:41]; a sandtrooper in Mos Eisley, prompted by Obi-Wan's influence through the Force, tell Luke to "Move along.  Move along." [43:51]; and Han says, "Stay sharp" twice, once to Chewbacca before making the jump to hyperspace away from Tatooine [56:08] and once to Luke shortly before the Death Star's sentry ships attack [1:34:15].

9:28 - Part of the fireworks display is apparently meant to resemble the opening crawl of the features:

10:31 - Hardeen (about his sniper rifle):  "Blast!  It's only good for one shot."  Obi-Wan also says "Blast!" when Jango Fett ambushes him in Attack of the Clones ("Blast!  This is why I hate flying!" [1:08:22]), and Luke says it twice in A New Hope:  after R2-D2 disappears ("Blast it!" [26:49]) and when a TIE fighter is behind him during the Battle of Yavin ("Blast it, Biggs, where are you?" [1:49:09]).

14:06 - Cad Bane (after discovering that Hardeen was Obi-Wan in disguise):  "Something smelled wrong about you from the start."  While not exactly the same, this seems to be an echo of what Leia says to Tarkin in A New Hope:  "I recognized your foul stench when I was brought on board" [57:17].

17:42 - The door opens to reveal Dooku at the end of a banquet table in the same way that Darth Vader is revealed in Cloud City in The Empire Strikes Back [1:28:20].

17:50 - Chancellor Palpatine: "It's a trap!"  Admiral Ackbar says, "It's a trap!" in Return of the Jedi [1:35:03], and Leia says it twice in The Empire Strikes Back [1:39:50].

20:02 - Obi-Wan (to Anakin):  "Are you alright?"  In The Phantom Menace, Anakin asks Qui-Gon, "Are you alright?" [1:17:31] and Padmé asks Anakin, "You alright?" [1:19:06].  In Attack of the Clones, Padmé asks Anakin, "Ani, are you alright?" [50:02], and later a clone trooper asks Padmé, "Are you alright?" [2:05:54].  In Revenge of the Sith, Anakin asks the Chancellor, "Are you alright?"[11:49], and a bit later, Mace Windu asks him, "Chancellor Palpatine, are you alright?" [24:53].  Padmé also asks Anakin, "Are you alright?" [1:27:59].  In A New Hope, Luke asks Obi-Wan this [59:16] and Biggs asks Luke [1:46:44], and in The Empire Strikes Back, Luke asks, "Rogue Two, are you alright?" [30:31].  Twice in The Empire Strikes Back, Han asks this with a shortened "You alright?" once to Luke [22:12] and once to Leia [31:39].  Luke also asks Han, "Are you alright?" when they're captured by Jabba in Return of the Jedi [28:31].

---

There are brief cues of the Imperial march at 15:18 (when Anakin expresses his anger that the Jedi council lied to him) and 17:31 (when he admits to the chancellor with some disdain that the plan to disguise Obi-Wan wasn't his).

The Clone Wars - S4E17 - "The Box"

3:05 - Yoda:  "Skywalker, a powerful Jedi you are."  He describes Anakin this way while speaking to Luke in The Empire Strikes Back, too:  "Oh, father, powerful Jedi was he" [55:18].

3:25 - Yoda (to Anakin, about Obi-Wan):  "If you leave, help him you could, but his future uncertain is."  He tells Luke something similar in The Empire Strikes Back:  "If you leave now, help them you could, but you would destroy all for which they have fought and suffered" [1:18:05].

7:38 - Hardeen: "Dioxis!  Breathe it, and you're dead."  In The Phantom Menace, Quin-Gon also announces "Dioxis" [5:20].

10:22 - Count Dooku (about Hardeen):  "Impressive."  Vader gives a similar compliment to Luke in The Empire Strikes Back:  "Impressive, most impressive" [1:44:30].

17:53 - Moralo Eval:  "This is not the first time you've saved everybody's skin, Hardeen."  Leia uses the same expression in A New Hope ("Somebody has to save our skins" [1:18:22]), and Anakin uses it in Revenge of the Sith (when he tells Obi-Wan, "Alright, but you owe me one, and not for saving your skin for the tenth time" [24:38]).

The Clone Wars - S4E16 - "Friends and Enemies"

3:25 - Cad Bane looks at a hat like Indiana Jones':

[source]

7:44 - Some of the panels in the background have the same hexagon pattern that's also seen in the homestead garage in Attack of the Clones and A New Hope:

9:02 - Obi-Wan (as Hardeen) reaches up to his bound feet to use the Force to release them.  There's a similar shot in The Empire Strikes Back where Luke reaches up in a vain attempt to free his own bound feet [9:01]:

12:49 - Cad Bane (about Hardeen's suggestion to split Eval's reward fifty-fifty):  "Over my dead corpse."

Hardeen:  "Don't tempt me."

There's a similar exchange in A New Hope.  After Greedo tells Han Solo that Jabba may take his (Han's) ship, Han says, "Over my dead body" to which Greedo replies, "That's the idea" [50:42].

16:31 - Moralo Eval:  "Who sells a ship with only enough fuel to get to this lousy rock?"  In A New Hope, Luke also disdainfully calls a planet a rock; after C-3PO asks if there's anything he can do to help, he replies, "Not unless you can alter time, speed up the harvest, or teleport me off this rock" [19:58].

19:47 - Anakin:  "You're going to pay for what you did."

Hardeen:  "You shouldn't have gotten involved."

There are two similarities here.  In Attack of the Clones, Anakin says almost the same thing:  "You're gonna pay for all the Jedi that you killed today, Dooku" [2:04:51], and in A New Hope, Obi-Wan uses the same expression when he tells Luke, "He [Luke's uncle] didn't hold with your father's ideals, thought he should have stayed here and not gotten involved" [32:42].

---

Moralo Eval's armor is similar to that of General Veers, Dengar, and the snowtroopers:

[source]

The helmet that Hardeen wears is based on a piece of Ralph McQuarrie concept art for Boba Fett:

[source]

It's even mentioned specifically in this video:

The Clone Wars - S4E15 - "Deception"

3:13 - This shot of Ahsoka and Plo Koon at Obi-Wan's fake funeral is somewhat similar to a shot of Anakin and Obi-Wan at Qui-Gon's funeral in The Phantom Menace [2:07:35]:

7:27 - Rako Hardeen (as he sees Obi-Wan disguised as him):  "What the?"  In Attack of the Clones, an alien on Coruscant makes this same exclamation as he sees Obi-Wan flying through traffic while hanging from a droid [15:08]; Han Solo says it in A New Hope after emerging from hyperspace into a meteor shower [1:03:15], and in Return of the Jedi, a scout trooper says this after being hit by Wicket [1:05:38].

---

According to the trivia in the episode guide on the Star Wars website (my source for both of these images), Hardeen's helmet is based on a rebel trooper concept from Return of the Jedi.

The Clone Wars - S4E14 - "A Friend in Need"

19:53 - Ahsoka (to R2-D2):  "That's two I owe ya."  Han Solo has a similar line in The Empire Strikes Back (speaking to Luke):  "That's two you owe me, junior" [17:00].

The Clone Wars - S4E13 - "Escape from Kadavo"

13:35 - Zygerrian slaver:  "Keeper, a fleet of warships has dropped out of hyperspace in sector six."  One of the rebels says something similar in The Empire Strikes Back:  "General, there's a fleet of Star Destroyers coming out of hyperspace in sector four" [22:31].

13:46 - Plo Koon:  "Wolf leader to Wolf pack, accelerate to attack speed."  Red Leader also says, "Accelerate to attack speed" in A New Hope [1:45:56], and Lando says it in Return of the Jedi [1:35:19].

14:22 - Ahsoka:  "We'll need a bigger ship."  In Jaws, Chief Brody says something similar to Quint:  "You're gonna need a bigger boat" [1:21:24].

15:20:  Warthog (after Plo Koon shoots down two Zygerrians):  "Yeah!  That got 'em!"  Wedge has a similar exclamation in The Empire Strikes Back after one of the AT-ATs is blown up:  "Wooah!  That got him!" [29:24].

15:25 - Plo Koon:  "Watch out for those towers."  There's also some talk about towers in the attack on the Death Star in A New Hope. At 1:53:48, Wedge says, "My scope shows the tower, but I can't see the exhaust port. Are you sure the computer can hit it?" and then, "What about that tower?" to which Luke replies, "You worry about those fighters; I'll worry about the tower."

16:49 - Anakin:  "We are running out of time."  Qui-Gon also says this in The Phantom Menace:  "Either way, we're running out of time" [40:07].

17:55 - Anakin (after destroying the towers with gun emplacements):  "You're all clear, Master Plo."  Han Solo uses this same expression near the end of A New Hope:  "You're all clear, kid.  Now let's blow this thing and go home." [1:56:54]