Gmail: How to search for multiple labels at once?

Searching on one label is pretty dang clear, click the label on the left-hand side, or type in Label:<search term> and hit "Search Mail".

 

But I am not clear on how to search for a message with a discrete set of labels.

 

Say I get an email that has both personal and business info in it. Instead of searching through all my business emails, or all personal one's, I want to only see email with both labels.

 

I use labels in their pure context, not as a modification of a folder system. I will label a message with up to three things. I may be personal, family and pertain to a specific topic I have a label for.

 

 

Anyone know how? I'm sure it's a simple operational search term item, but I haven't nailed it yet.