Moments that follow the concept in the Music of the Ainur...

[Peter_20]

According to the Ainulindalë, Arda was prophesied to change all evil things to good, and we see some examples on this in the very same chapter: Melkor tries to freeze and dry up the waters, but instead creates the snow and the rain.
Melkor (Morgoth :p) also sends blinding fogs over Hithlum, but these very fogs help Fingon to arrive safely to the rescue of Maedhros.

I find this very fascinating, and I was just wondering if you have found other events that follow the Music of the Ainur like this? :)

[Landroval]

There is an interesting refference which underlies your idea in HoME X - quite long:
Manwe was the spirit of greatest wisdom and prudence in Arda. He is represented as having had the greatest knowledge of the Music, as a whole, possessed by any one finite mind; and he alone of all persons or minds in that time is represented as having the power of direct recourse to and communication with Eru. He must have grasped with great clarity what even we may perceive dimly: that it was the essential mode of the process of 'history' in Arda that evil should constantly arise, and that out of it new good should constantly come. One especial aspect of this is the strange way in which the evils of the Marrer, or his inheritors, are turned into weapons against evil. If we consider the situation after the escape of Morgoth and the reestablish¬ment of his abode in Middle-earth, we shall see that the heroic Noldor were the best possible weapon with which to keep Morgoth at bay, virtually besieged, and at any rate fully occupied, on the northern fringe of Middle-earth, without provoking him to a frenzy of nihilistic destruction. And in the meanwhile, Men, or the best elements in Mankind, shaking off his shadow, came into contact with a people who had actually seen and experi¬enced the Blessed Realm.
Tolkien considered your idea to apply in real life as well:
All we do know, and that to a large extent by direct experience, is that evil labours with vast power and perpetual success – in vain: preparing always only the soil for unexpected good to sprout in. So it is in general, and so it is in our own lives.