Warning

Instant

Prevent all combat damage that would be dealt by target attacking creature this turn.

Discussion (1)

berryjon on Advice on Player and Rules

2 years ago

Short answer, you're in the right. You can cast pump spells after blockers are declared, and before damage is allocated.

Long answer: Rule 509 of the Comprehensive rules spells it out, though in a long winded manner.

You declare Attackers.
You and your opponent, in priority order, put triggered abilities on the stack.
You and your opponent, in priority order, can cast spells or activate abilities.
Resolve the stack.

Your opponent declares blockers.
You and your opponent, in priority order, put triggered abilities on the stack.
You and your opponent, in priority order, can cast spells or activate abilities.
Resolve the stack.

Move on to the Combat Damage step.

What this means is that when you declare your attackers, before the opponent decides on blockers, they can do things like cast Bright Reprisal or Warning on one of your attacking creatures. You can also, for example, cast Jump on one of your creatures to give it flying before the opponent can declare a blocker for it.

Then the opponent declares their blockers. After that has been decided, each of you, in priority, can cast spells again. You can cast Giant Growth on your attacking creature here, and they can cast cards like Hold the Line or activate the ability on Angelic Page or General Jarkeld (and he's just a bundle of laughs, let me tell you).

Then, once everything is resolved, is damage dealt.