How to add custom text to WordPress login page

If for some reason you need to display a custom message on WordPress login page, here is a quick and easy recipe to do it.
Nothing complicated, paste the code below in your functions.php file. Message can be customized on line 3.

function wps_login_message( $message ) {
    if ( empty($message) ){
        return "<p class='message'>Welcome to this site. Please log in to continue</p>";
    } else {
        return $message;
    }
}
add_filter( 'login_message', 'wps_login_message' );