Error with dbQuery

$tbl = $modx->getFullTableName("site_content");
$sql = "SELECT id, parent, contentLang, refId FROM $tbl";
$rs = $modx->dbQuery($sql);
while ($curPage = $modx->fetchRow($rs)) {
  if ($curPage['parent'] != 0) {
    $sql = "SELECT id, parent, contentLang, refId FROM $tbl WHERE id = ".$curPage['parent'];
    $modx->event->alert($sql);
    $rs2 = $modx->dbQuery($sql);
    if ($parent = $modx->dbQuery($rs2)) {
    }
  }
}

« MODx Parse Error »
MODx encountered the following error while attempting to parse the requested resource:
« Execution of a query to the database failed - You have an error in your SQL syntax. Check the manual that corresponds to your MySQL server version for the right syntax to use near 'Resource id #24' at line 1 »
      SQL: Resource id #24
      [Copy SQL to ClipBoard]
 
Parser timing
  MySQL: 	0.0011 s s	(5 Requests)
  PHP: 	1136754939.3584 s s	 
  Total: 	1136754939.3596 s s

    $rs2 = $modx->dbQuery($sql);
    if ($parent = $modx->dbQuery($rs2)) {
    }

    $rs2 = $modx->dbQuery($sql);
    if ($parent = $modx->fetchRow($rs2)) {
    }