The 32-year-old, who won the Premier League, Champions League and two FA Cups with his former club Chelsea, thinks Arsenal can challenge in all competitions this season.
“I came here with the ambition to fight for the Premier League title, I want to fight for other competitions also.
“It was like that at the other clubs I have been at but it was not always easy, there were difficult moments.
“I am going to try to do my best every single day and try to help everyone to believe in this because I think this club can believe a lot because it has a lot of potential.
“Football is about the end not the beginning and we are going to have to try to fight to the end.”