ruby on rails - RoR: rendering devise login into application layout -

i'm trying render devise sign in page "devise/sessions/new" application layout, i'm wondering how so?

if this:

<%= render "devise/sessions/new" %> 

i error:

actionview::missingtemplate in static#index missing partial devise/sessions/new {:locale=>[:en], :formats=>[:html], :handlers=>[:erb, :builder, :coffee]}. searched in: 

if try this:

<%= render :template => "devise/sessions/new" %> 

i error:

nameerror in users#show undefined local variable or method `resource' 

where have form:

<%= form_for(resource, :as => resource_name, :url => session_path(resource_name)) |f| %> 

i'm trying bring sign in form application layout, if possible.

whats name have used sign in page. if - "new.html.erb", rename "_new.html.erb". then,

<%= render "devise/sessions/new" %> 

will work.

for second issue, coming again after above thing.

nameerror in users#show undefined local variable or method `resource' 

as can see, no variable can found in 'show' action, need define variable. which, form data. go through, forms , flow rails app, once again.