§ Ainulindalë The Silmarillion

And many other things Ilúvatar spoke to the Ainur at that time, and because of their memory of his words, and the knowledge that each has of the music that he himself made, the Ainur know much of what was, and is, and is to come, and few things are unseen by them. Yet some things there are that they cannot see, neither alone nor taking counsel together; for to none but himself has Ilúvatar revealed all that he has in store, and in every age there come forth things that are new and have no foretelling, for they do not proceed from the past. And so it was that as this vision of the World was played before them, the Ainur saw that it contained things which they had not thought. And they saw with amazement the coming of the Children of Ilúvatar, and the habitation that was prepared for them; and they perceived that they themselves in the labour of their music had been busy with the preparation of this dwelling, and yet knew not that it had any purpose beyond its own beauty. For the Children of Ilúvatar were conceived by him alone; and they came with the third theme, and were not in the theme which Ilúvatar propounded at the beginning, and none of the Ainur had part in their making. Therefore when they beheld them, the more did they love them, being things other than themselves, strange and free, wherein they saw the mind of Ilúvatar reflected anew, and learned yet a little more of his wisdom, which otherwise had been hidden even from the Ainur.