Pourquoi mes erreurs de validation Laravel 5.2 ne s'affichent-elles pas dans ma vue Blade ?

public function saveUser(Request $request) {
    $this->validate($request, [
        'name' => 'required|max:120',
        'email' => 'required|email|unique:users',
        'phone' => 'required|min:11|numeric',
        'course_id' => 'required'
    ]);

    $user = new User();
    $user->name = $request->input(['name']);
    $user->email = $request->input(['email']);
    $user->phone = $request->input(['phone']);
    $user->date = date('Y-m-d');
    $user->completed_status = '0';
    $user->course_id = $request->input(['course_id']);
    $user->save();
    return redirect('success');
}

@if(count($errors) > 0)
    <div>

protected function mapWebRoutes(Router $router)
{
    $router->group([
        'namespace' => $this->namespace,
        // Remove the 'web' middleware
    ], function ($router) {
        require app_path('Http/routes.php');
    });
}