Rails render wrong match html tag -

Some of the content of my posts & lt; / Div & gt; are tags, so when I post by body:

  <% = simple_format (post.body)%>   
 The format will be in horrible disorder.  
 How to do it correctly?   
 
 
 You can  post.body  in  & lt; / Div & gt;  can get rid of: <: / P> 
  <% = simple_format (post.body.gsub ('& lt; / div>', ''))% & Gt;