Problem with a PHP code

<?php

use Illuminate\Support\Facades\Route;
use Illuminate\Http\Request;
/*
|--------------------------------------------------------------------------
| Web Routes
|--------------------------------------------------------------------------
|
| Here is where you can register web routes for your application. These
| routes are loaded by the RouteServiceProvider within a group which
| contains the "web" middleware group. Now create something great!
|
*/

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

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

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

Route::post('contact', function()
{
    $data = Request::all();
    $rules = array(
        'subject' => 'required',
        'message' => 'required'
    );

    $validator = Validator::make($data, $rules);

    if($validator-> fails())
    {
        return Redirect::to('contact')->withErrors($validator)->withInput();
    }

    return 'Your message has been sent';
});

Non-static method Illuminate\Http\Request::all() should not be called statically