Old Input
Laravel allows you to keep input from one request during the next request. This feature is particularly useful for re-populating forms after detecting validation errors. However, if you are using Laravel's included validation services, it is unlikely you will need to manually use these methods, as some of Laravel's built-in validation facilities will call them automatically.
Flashing Input To The Session
The flash method on the IlluminateHttpRequest instance will flash the current input to the session so that it is available during the user's next request to the application: