The Grace of Ilúvatar?

[Bêthberry]

Originally Posted by Frodo Baggins

Well, if Eru is never decieved by intentions behind repentace the Valar certainly were. Maybe I'm wrong but Nienna's pity got in the way of her seeing the truth and Manwe was deluded enough to let Morgoth go the first time.

I'm not sure this is the most understanding way to think of Nienna's pity (or Manwe's delusion).

Consider Gandalf's words to Frodo--and Gandalf spent a great deal of time in Nienna's house--about showing Gollem pity. The worth or value of pity lies in offering hope for change, reformation, salvation. Without pity there is no possibility that those who have fallen by the wayside will ever be shown how to earn a way back. The plot of LotR demonstrates that vengeance lies not with hobbit or man, dwarf or elf, but with the faith which provides for eucatastrophe. Seen in this light, pity is part of the truth.