The docs for sentry (and I would) recommend using a try catch on the server side validation routine instead. Sentry Documentation
Specifically catch the Cartalyst\Sentry\Users\WrongPasswordException and set your own error message
try
{
// Set login credentials
$credentials = array(
'email' => 'john.doe@example.com',
'password' => 'test',
);
// Try to authenticate the user
$user = Sentry::authenticate($credentials, false);
}
catch (Cartalyst\Sentry\Users\WrongPasswordException $e)
{
echo 'Wrong Login Info, try again.';
}