Barca have been rocked by the manner of their Champions League thrashing by Bayern Munich.
Guardiola was asked whether he would go back to his boyhood club and was quoted as saying by local press: "That chapter is closed. It was a fantastic chapter, but, as in life, one is born, grows and evolves."
He reflected on his "happy" time with the club and the "wonderful relationship" he enjoyed with the players and staff, but reiterated that it was over.
"I was happy at Barcelona," he said. "I had a wonderful relationship with the people I worked with.
"I am very proud to have been part of Barcelona, but life goes on and we need to pursue other goals. I felt a very large peace with myself when I left. I did the best I could.
"Everything has a beginning and an end. And the end comes when you discover that it's enough."
He added: "When you make the decision to leave a club, it's better than when the decision is taken for you."