laravel throwing MethodNotAllowedHttpException

Question

 I wanted to create a login form and make sure that data is posted successfully by printing it in the next form. But  I am getting this exception:

Symfony \ Component \ HttpKernel \ Exception \ MethodNotAllowedHttpException

My MemberController.php:

    public function index()
    {
        if (Session::has('userToken'))
        {
            /*Retrieve data of user from DB using token & Load view*/
            return View::make('members/profile');
        }else{
            return View::make('members/login');
        }
    }

    public function validateCredentials()
    {
        if(Input::post())
        {
            $email = Input::post('email');
            $password = Input::post('password');
            return "Email: " . $email . " and Password: " . $password;
        }else{
            return View::make('members/login');
        }
    }

The routes has:

Route::get('/', function()
{
    return View::make('hello');
});

Route::get('/members', 'MemberController@index');
Route::get('/validate', 'MemberController@validateCredentials');

The view login.php has this form direction:

<?php echo Form::open(array('action' => 'MemberController@validateCredentials')); ?>

Can someone help me solve this?