Zealous Persecution and new creatures

[lordofthepit]

Do creatures that come into play on your side after Zealous Persecution resolves get the +1/+1 bonus? Conversely, do creatures that come into play on your opponent's side get the -1/-1 (I presume the same answer)? What about you stealing control of an opponent's creature or vice versa, after Persecution resolves?

I assume the bonus is only applied at resolution, since that's how Rain of Filth works, but I actually don't know why.

[Koby]

Zealous Persecution provides a continuous effect that gives a bonus to all creatures on the battlefield at the time of resolution. It's not an effect from a permanent like Crusade. It's no different than Overrun. I'm not sure why the formatting is flipped around between the two cards.

The bonus/negative only affect creatures that were on the battlefield at the time of resolution of the spell.

[cdr]

The Continuous Effects section (hhttp://yawgatog.com/resources/magic-rules/#R611) of the rules is what you want.

611.2c. If a continuous effect generated by the resolution of a spell or ability modifies the characteristics or changes the controller of any objects, the set of objects it affects is determined when that continuous effect begins. After that point, the set won't change. (Note that this works differently than a continuous effect from a static ability.) A continuous effect generated by the resolution of a spell or ability that doesn't modify the characteristics or change the controller of any objects modifies the rules of the game, so it can affect objects that weren't affected when that continuous effect began.

Example: An effect that reads "All white creatures get +1/+1 until end of turn" gives the bonus to all permanents that are white creatures when the spell or ability resolves--even if they change color later--and doesn't affect those that enter the battlefield or turn white afterward.

The "until end of turn" is first on Zealous Persecution for clarity.