Rules of Instants. MTG

Question

If I were to attack with my creatures, 5 1/1's for say, and my opponent chooses not to block, could I then boost those creatures with an instant to make them more powerful?

Answer 1

Yes, you can do that.

The combat phase is divided into 5 separate steps:

• 1) Beginning of Combat
• 2) Declare Attackers
• 3) Declare Blockers
• 4) Damage Assignment
• 5) End of Combat

In the Declare Blockers step, after the defending player has decided how to block the attacking creatures, each player gets priority before moving on to Damage Assignment. When the attacking player has priority, they can cast an instant or activate an ability that would pump the attacking creatures.

From the Basic Rulebook:

3. Combat Phase

   c. Declare blockers step

   <blockquote>
     <p>Your opponent decides which, if any, of his or her
     untapped creatures will block your attacking creatures,
     then they do so. If multiple creatures block a single
     attacker, you order the blockers to show which is fi rst
     in line for damage, which is second, and so on. <strong>Players
     can then cast instants and activate abilities.</strong></p>
   </blockquote>