No mischief worthier of our fear <br />In nature can be found <br />Than friendship, in ostent sincere, <br />But hollow and unsound, <br />For lull'd into a dangerous dream <br />We close infold a foe, <br />Who strikes, when most secure we seem, <br />The inevitable blow.<br /><br />William Cowper<br /><br />http://www.poemhunter.com/poem/on-flatteries-from-the-greek/
