$("form#pessoasCadastrar" ).submit(function( event ) {

    event.preventDefault();

    data = $("form#pessoasCadastrar" ).serialize(),
    url = '/pessoas/salvar',

    var posting = $.post( url, { formData: data } );
    posting.done(function( data ) {
    if(data.fail) {
      $.each(data.errors, function( index, value ) {
        var errorDiv = '#'+index+'_error';
        $(errorDiv).addClass('required');
        $(errorDiv).empty().append(value);
      });
      $('#successMessage').empty();
    }
    if(data.success) {
        $('.register').fadeOut(); //hiding Reg form
        var successContent = '<div class="message"><h3>Registration Completed Successfully</h3><h4>Please Login With the Following Details</h4><div class="userDetails"><p><span>Email:</span>'+data.email+'</p><p><span>Password:********</span></p></div></div>';
      $('#successMessage').html(successContent);
    } //success
  }); //done
});

public function rules(){ ... }
public function messages(){ .... }

public function response(array $errors)
{
    if ($this->ajax() || $this->wantsJson())
    {
        return response()->json($errors, 422);
    }
       $dados = array('fail' => true, 'errors' => $errors);
       return response()->json(array('fail' => true,'errors' => $errors));
}

public function salvar(PessoaRequest $request){

 $p = new Pessoa();
 [....]

 return Response()->json(array('success' => true,$request->all()));

{"fail":true,"errors":{"nome":["O campo nome u00e9 obrigatu00f3rio!"]}}