The Raid ability of a spell checks to see if its condition is true when the spell (in this case Howl of The Horde) resolves, not when its delayed trigger is triggered. That condition of course is if you attacked this turn. Remembering this should make it pretty easy: Casting Howl of the Horde during your pre-combat main phase provides one copy of your next instant or sorcery being placed on the stack. Casting it during your post-combat main phase, after you have attacked, will result in two copies of your next instant or sorcery being placed on the stack. Easy as that! If you’re feeling explosive, why not cast it post-attack and then cast another Howl of the Horde for a total of four delayed triggers? (The first Howl creates two copies of the second Howl, which means a total of 3 Howls, each of which creates two more copies of the next spell cast). Cast a final Lightning Strike after that and you might as well win outright- That’s 21 damage (6 copies plus the original Strike)! Just remember to cast your next instant or sorcery in the same turn you cast Howl of the Horde, or you lose the delayed trigger(s) forever.
Today’s Rules Tip written by Daniel Clarke