Idiom: Quitters never win; winners never quit
If you quit you will never get what you want, but if you keep trying you will find a way to get what you want.
('Quitters never win, winners never quit, but those who never win and never quit are idiots' is a variation accredited to Larry Kersten)
Buy our lists of British English, American English and Animal idioms in PDF format. They're perfect to use offline for reference or for use in class!