One of these things is not like the others
"General Kenobi, years ago you served my father in the Clone Wars."
"He has too much of his father in him."
"Join me, and together we can rule the galaxy as father and son."
"Your father he is."
Please go to the Question #17 post if you haven't had a chance work on this one yet, since the text below contains the solution.
Each of the quotes is from the Star Wars films.
The first is spoken by Princess Leia (or a holographic image of her, anyway) in the original 1977 film. She is asking for Obi-Wan Kenobi to help the rebellion, based on the fact that he had helped her (adoptive) father years previous.
The second quote is spoken by Aunt Beru, referring to how Luke Skywalker is too much like his father (Anakin) to simply be a farmer. This quote is also from the original Star Wars film ("Episode IV").
Darth Vader speaks the third quote to Luke in The Empire Strikes Back, in the scene in which he reveals that he is Luke's father.
The last quote is from Yoda, in Return of the Jedi, confirming to Luke that Vader was telling the truth -- he is indeed Luke's father.
The commonality is who the "father" refers to in each of the quotes. Darth Vader / Anakin Skywalker is the father in the last three quotes. Princess Leia, however, was certainly not referring to Vader when she tried to enlist Kenobi's help. So that is the quote which does not belong. It is not like the others.