Never say never
Meaning you should not declare that something will never happen or is impossible, because it might happen in the future. It's a reminder to remain open-minded and flexible, as situations and people can change, and unexpected possibilities can arise.
The idiom suggests that life is full of surprises and that it's unwise to dismiss any possibility. It promotes an attitude of not being closed off to new experiences or opportunities. The core idea is not to take the word "never" too literally, but to avoid making definitive statements about the future.
Nothing is impossible, anything can happen, as in Mary said Tom would never call her again, but I told her, “Never say never.” This expression was first recorded in Charles Dickens's Pickwick Papers (1837).
Canadian singer Justin Bieber also wrote a song titled "Never Say Never". The song is used as the theme song for the 2010 film The Karate Kid, and features a rap verse from its star, Jaden Smith.