// ...

$input = Input::all();

$rules = [
    'password' => 'required|min:8',
    'password_confirmation' => 'required|min:8|same:password',
];

$messages = [
    'password_confirmation.same' => 'Password Confirmation should match the Password',
];
$validator = Validator::make($input, $rules, $messages);

if ($validator->fails()) {
    return back()->withInput()->withErrors($validator->messages());
}
// ...