Amp and cabinet power rating?

[Konjurer]

Firstly my excuses for the n00b-question, I never really took the time to understand this.
What's the relation between the power rating for an amp head and the power rating for a cabinet? I know that when, for example, a 4 ohm cabinet is connected to a 1000W bass amp, the amp puts out the power which it's rated for at 4 ohms (1000W in this case). But the cabinet has a 500W power rating, what does this 500W exactly mean for the setup?

Thanks in advance!

 

[Trevoire520]

In this situation you could blow the cab if you turn the amp up too loud. Be careful.

 

[53Crëw]

+1. You want your speaker cab to exceed the output power rating of the amp so you don't damage the speakers.