I am in Sancre Tor trying to obtain the armor in this part of the main quest. I have killed (or released) the three undead blades as I am supposed to do. Their spirits then go to the main tomb in order to lift the evil enchantment on the armor. Unfortunately all they do is kneel down for ages. No enchantment is lifted and I cannot get the armor. I am wondering whether the order in which I do these events is crucial. Can anyone help with this? Thanks.

There are four to kill.

http://www.uesp.net/wiki/Oblivion:Blood_of_the_Divines

No, there is some kind of bug here. Even though I have killed all four undead only three undead ghosts appear at the shrine. The walkthrough gives a semi solution but it doea not make all four spirits appear.

What does your latest journal entry say for this quest?

Note that you have to kill 5 undead actually, because you have to kill the Warden to get into the prison. You should have acquired 4 leveled enchanted items; an amulet, a shield, and two named swords, which the four Blades are carrying.

My latest journal entry does say that I have killed all the undead blades and I should proceed to the shrine where the ghosts will dispel the evil barrier. The red quest marker points only to the shrine and does not indicate any more undead need to be found. As I said there is a bug that makes Valdemar appear twice instead of another undead. There is a console fix for this but it still only leaves three spirits in the shrine. Wierd.

I just finished this quest. This is prob a silly question but did you wait? For me it took awhile for the rested soul to walk to the shrine and release the enchantment. Maybe the ghost is caught in the dungeon and needs a nudge?