Owen Lars refuses to raise the son of a stepbrother he barely knows and Obi-Wan has to raise Luke on his own. He's wary of having to raise Luke when being Anakin's Master ended so badly but he doesn't really have a choice.
What he doesn't except is how much he end up caring for and loving Luke. When the message from Princess Leia is delivered to him, he has stopped thinking of Luke as Anakin and Padme's son years ago and has started thinking of him as his own.
So he leave Luke on Dagobah with Yoda and then go to help her on his own. Even if he knows he's only delaying the inevitable, at least Luke will stay safe just a bit longer.
Bonus :
- Obi-Wan teach Leia about the Force, and before dying (or after as a force ghost) he tell her that she has a brother and that she needs to go to Dagobah - Luke feels Obi-Wan's death and immediately try to leave Dagobah but force ghost! Obi-Wan appears and tell him to wait because someone who need his help is coming - When Vader eventually tell Luke that he's his father, Luke replies with "No, Obi-Wan was my father" and he only stop Leia from killing Vader because he knows that Obi-Wan wouldn't have wanted either of them to do that (because he loved Anakin Skywalker and because he doesn't want Luke and Leia to live with having killed their own father)
Obi-Wan can't sacrifice Luke to the cause
What he doesn't except is how much he end up caring for and loving Luke. When the message from Princess Leia is delivered to him, he has stopped thinking of Luke as Anakin and Padme's son years ago and has started thinking of him as his own.
Obi-Wan can't resolve himself to send his son to fight the Empire, even if he's the only hope of the galaxy. But he can't just leave Leia either, he promised Padmé that he would take care of her and she's Luke's sister ...
So he leave Luke on Dagobah with Yoda and then go to help her on his own. Even if he knows he's only delaying the inevitable, at least Luke will stay safe just a bit longer.
Bonus :
- Obi-Wan teach Leia about the Force, and before dying (or after as a force ghost) he tell her that she has a brother and that she needs to go to Dagobah
- Luke feels Obi-Wan's death and immediately try to leave Dagobah but force ghost! Obi-Wan appears and tell him to wait because someone who need his help is coming
- When Vader eventually tell Luke that he's his father, Luke replies with "No, Obi-Wan was my father" and he only stop Leia from killing Vader because he knows that Obi-Wan wouldn't have wanted either of them to do that (because he loved Anakin Skywalker and because he doesn't want Luke and Leia to live with having killed their own father)