diff --git a/lisp/paren.el b/lisp/paren.el
index d3e3df0046e..c5b26b83bbf 100644
--- a/lisp/paren.el
+++ b/lisp/paren.el
@@ -44,7 +44,8 @@
   "Toggle Show Paren mode.
 When Show Paren mode is enabled, any matching parenthesis is highlighted
 after `show-paren-delay' seconds of Emacs idle time.
-You must modify via \\[customize] for this variable to have an effect."
+This variable should be set only with \\[customize], which is equivalent
+to using the function `show-paren-mode'.
   :set (lambda (symbol value)
 	 (show-paren-mode (or value 0)))
   :initialize 'custom-initialize-default