How do i display LOGIN message to not logged in users

Hi how can i display message to non logged in users without changing the core?

I have used following code . But it has no effect.

<?php if(is_user_logged_in()){
                                                if ( function_exists( 'wfp_button' ) ) wfp_button();
                                            }else{
                                                sprintf(__( 'You must be <a href="%s">Logged in</a> to post a comment.' ), site_url('/einloggen?action=login&redirect_to=' . get_permalink()) );

                                            }
                                           ?>

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