Forwarding emails from gmail

I observed that I cannot forward multiple emails from my gmail account. I tried creating a filter and clicked on the checkbox that applies the filter rule to all the emails. But the filter does not really apply to old emails. So I tried making these emails "New" or "Unread" and that still did not seem to do the trick.

I like the idea of using one gmail account so I can check the emails from my iPhone, but I also need the flexibility to forward a bulk set of emails once in a while to my personal mailbox, as I don't want to rely on gmail in the very long run. Besides it has a limit of 6 GB, so I am sure, I will need more space eventually.