Voltage rating vs. power rating of a resistor
The voltage rating is for the resistor series typically and specifies the maximum peak voltage you can apply without danger of damaging the resistor due to corona, breakdown, arcing, etc.

The power rating is completely independent of the voltage rating. It specifies the maximum steady state power the package is able to dissipate under given conditions.

You have to conform to both specs. If placing the maximum voltage across the resistor results in more power than the spec allows you have to reduce the voltage until you meet the spec.  Likewise you can't increase the voltage above the rating just because you're not hitting the maximum power limit.