When you cast Divine Deflection, you choose a single target, which is what any prevented damage will then be dealt to. This sets up a “shield” for the next X damage that would be dealt to you and/or permanents you control. That’s a TOTAL of X damage, and you can decide which damage is going to be prevented the next time damage would be dealt to you or your creatures. Immediately after the damage is prevented, that same amount of damage is dealt to the target you chose as you cast Divine Deflection.
Examples help to clear things up! Let’s say your opponent casts Slagstorm, choosing to damage all creatures. You control three 3/3 creatures, and you cast Divine Deflection with X=3, and target your opponent. You now essentially have 3 “shields” to prevent 1 damage each. As Slagstorm resolves, you can choose how to divvy up those shields among your creatures. The most logical choice here is to apply 1 “shield” to each of your creatures, so they are dealt only 2 damage each and survive the Slagstorm, while your opponent is dealt 3 damage. (You don’t get to prevent 3 damage to EACH creature, and deal 9 damage to the opponent.)
When damage is prevented, Divine Deflection deals noncombat damage to whatever you targeted. So if you targeted a player, you could choose to redirect the damage it would deal to a planeswalker that player controls instead.
Another important distinction is that the source of the damage is Divine Deflection itself, rather than the source that had its damage prevented. This is different from a redirection effect, so even if damage from a lifelink or infect creature is prevented, the damage that is dealt by Divine Deflection will just be normal damage from a white source.
Today’s Rules Tip written by
Josh Stansfield, Level 2 judge from Orange, CA