InvalidArgumentException in UrlGenerator.php in laravel 5.1

I am getting an error that says "InvalidArgumentException in UrlGenerator.php line 306: Route [main.show] not defined."

here is my redirect route: return redirect()->route('main.show',$comment->rest->id);

I am trying to redirect show.blade.php file which is located in main folder with rest id. But it shows me this error. Now please help to redirect show.blade.php with rest id.(here rest id can be found by $comment->rest->id)

via Chebli Mohamed