Sasuke’s defeat to Gaara, and later Itachi, forces him to realize that he is not strong enough to get revenge against his older brother.
That's because
you're still weak, Little Sasuke!
!ذلك لأنّك لا زلتَ ضعيفًا يا ساسكي الصغير
Isso tudo porque você ainda
 é um fracote, Sasukezinho!