In a previous question Nathan Long answer this

The targeting restriction of the Surge is “target red or black creature that's attacking or blocking”. It's describing what object can be targeted by the Surge (a creature that red or black and is also attacking or blocking).

A better comparison for Pyroblast is Red Elemental Blast. Pyroblast can target any spell, but will only counter the spell if the spell is blue. Red Elemental Blast can only target a blue spell, since the targeting requirement is “target blue spell”, while the targeting requirement for Pyroblast is just “target spell”.

But due to this I cannot find the difference from Pyroblast and Surge. Both says target red/black or spell and after put a check of characteristics. Why Pyro check in resolution and Surge in choosing target step? The reason is “that” instead of “if”. If so is a general rule that we can apply?

Thank you

Originally posted by Andrea Sciarrotta:

Why Pyro check in resolution and Surge in choosing target step? The reason is “that” instead of “if”. If so is a general rule that we can apply?

The difference in wording between the two is indeed the difference–it's a matter of how the English language works.

The phrase “black or red creature that's attacking or blocking” is by itself a noun phrase, a complete description of an object–the base noun is “creature” and “that's attacking or blocking” is a relative clause that modifies that base noun by restricting it, just as the adjectives “black or red” also restrict it. The phrase “that's attacking or blocking” on Surge of Righteousness is therefore part of the targeting requirements, since it's part of the description of the object being targeted.

By contrast, the phrase “spell if it's blue” is not by itself a complete description of an object–it's a nonsense fragment. “If” is a conjunction that expresses a condition, but in order to make sense that condition has to be applied to a verb or independent clause, and neither of those are present in this fragment. The phrase “if it's blue” on Pyroblast must therefore be applying a condition to the verb “counter” (or “destroy”)–it's a modification of the action that will be performed.