--- /wp-includes/post-template.php	Sun Jul 24 13:12:23 2016
+++ /wp-includes/temp/post-template.php	Sun Jul 24 14:08:32 2016
@@ -1531,7 +1531,12 @@
 function get_the_password_form( $post = 0 ) {
 	$post = get_post( $post );
 	$label = 'pwbox-' . ( empty($post->ID) ? rand() : $post->ID );
-	$output = '<form action="' . esc_url( site_url( 'wp-login.php?action=postpass', 'login_post' ) ) . '" class="post-password-form" method="post">
+
+	// Display error message if post password is incorrect
+	if ( isset( $_COOKIE['wp-postpass_' . COOKIEHASH] ) )
+		echo '<p><strong>' . get_the_password_form_wrong_password() . '</strong></p>';
+
+	$output .= '<form action="' . esc_url( site_url( 'wp-login.php?action=postpass', 'login_post' ) ) . '" class="post-password-form" method="post">
 	<p>' . __( 'This content is password protected. To view it please enter your password below:' ) . '</p>
 	<p><label for="' . $label . '">' . __( 'Password:' ) . ' <input name="post_password" id="' . $label . '" type="password" size="20" /></label> <input type="submit" name="Submit" value="' . esc_attr_x( 'Enter', 'post password form' ) . '" /></p></form>
 	';
@@ -1548,6 +1553,27 @@
 	 * @param string $output The password form HTML output.
 	 */
 	return apply_filters( 'the_password_form', $output );
+}
+
+/**
+ * Displays message if incorrect password supplied on protected post.
+ *
+ * @since 4.5.2
+ *
+ * @return string HTML content for the error message if post password inputted incorrectly.
+ */
+function get_the_password_form_wrong_password() {
+
+	$output = esc_html_x('Wrong password. Please try again.', 'incorrect post password');
+
+	/**
+	 * Filter the HTML output for the error message if post password inputted incorrectly.
+	 *
+	 * @since 4.5.2
+	 *
+	 * @param string $output The error message output.
+	 */
+	return apply_filters( 'the_password_form_wrong_password', $output );
 }