How to pass an Variable to an Partial?!?

Hello,
I'm new in Rails and I'm Trying to implement a plattform were
authorized people can apply Profiles to a special topic.
The profil can be identified by the ID and the title in the data
base.
So in the view/profil/show_profil.html.erb the infomation of one
Profil are perfektly shown.

My problem:
I have an data base table called : "comment" in which I save comments
users made to one Profil, identifed by the Profil ID which I also save
in this table.
My Idea was to invoke an partial in the View/profil/
show_profil.html.erb... something like:

          <%= render :partial => "comments/comments_show" %>

But how can I find and show the comments with the ID of the used
Profil?!?!?
Can I handover the Profil_ID somehow and if so how can I use it?

It was hard for me to explain my problem and I hope this was
understandable.
Hope to get some Ideas and solutions.

Have a look at the docs at
http://rails.rubyonrails.org/classes/ActionController/Base.html to see
how to pass data to a partial. A google search for render partial
puts this as the first hit.

Colin