Empty error

<?php
include ("config.php");


if (isset($_POST['login'])) {
    $time = time();
    $sql = $db->query("SELECT * FROM `Members` WHERE `user`='{$_POST['user']}'");
    $rows = $db->num_rows($sql);
    $result = $db->fetch_object($sql);
    
    if (empty($_POST['user'])) {
        echo "You forgot something.";
    }
}
?>
	<table width="55%" align="center">
		<form method="post" action="">
			<tr>
				<td class="title" colspan="2">Login</td>
			</tr>
			<tr>
				<td class="box">Username:</td>
				<td class="box"><input type="text" name="user"></td>
			</tr>
			<tr>
				<td class="box">Password:</td>
				<td class="box"><input type="password" name="password"></td>
			</tr>
			<tr>
				<td class="box"></td>
				<td class="box"><input type="submit" name="login" value="Login" style="width: 120px;"></td>
			</tr>
		</form>
	</table>