I have a level 5 paladin. My paladin has a couple of powers that subject enemies to my Divine Sanction. I also have Divine Challenge. As far as I can tell these are almost the same thing - are they?
Despite their functional and naming similarities, Divine Challenge and Divine Sanction are quite different.
Divine Challenge is a Paladin class power, minor action, close burst 5, that allows the Paladin to mark an enemy. The mark lasts until this power is used again. The Paladin must engage this target by attacking the target or ending his or her turn adjacent to it or the mark ends. If the target makes an attack that does not include the Paladin, it takes 3/6/9+CHA mod radiant damage.
Divine Sanction is an effect of certain attack powers (such as Ardent Strike) which counts as a mark and, if the target makes an attack that does not include the creature that placed the Divine Sanction, it takes 3/6/9+CHA mod radiant damage. Divine Sanction ends when the power that applies it specifies that it ends.
There are a number of important differences:
No, there's a subtle, but distinct, difference between the two. Divine challenge is essentially the paladin's mark. He can do it any time as a minor action. Divine Sanction is essentially a second marking ability the paladin has that is usually granted through the use of a power. A paladin can actually mark multiple creatures using these two in tandem.
You can have one Divine Challenge up at a time, but Divine Sanction can mark as many creatures as your powers allow.