Divine Sanction is just a EONT Divine Challenge without the mark, correct?
Also I read polearms are good weapon for them, but you need a lot of feats for them. Is there a good polearm feat combo?
Divine Sanction is a mark + capacity to deal damage if enemy ignore. That last as long as the power who created it state it.
Divine Challenge is a special case of a Divine Sanction, and last as long as you met the requirement of the Divine Challenge
Some power mark. You wont deal damage if they ignore you.