John Tolkien: The Silmarillion

But the other Ainur looked upon this habitation set within the vast spaces of the World, which the Elves call Arda, the Earth; and their hearts rejoiced in light, and their eyes beholding many colours were filled with gladness; but because of the roaring of the sea they felt a great unquiet. And they observed the winds and the air, and the matters of which Arda was made, of iron and stone and silver and gold and many substances: but of all these water they most greatly praised. And it is said by the Eldar that in water there lives yet the echo of the Music of the Ainur more than in any substance else that is in this Earth; and many of the Children of Ilúvatar hearken still unsated to the voices of the Sea, and yet know not for what they listen.

Now to water had that Ainu whom the Elves can Ulmo turned his thought, and of all most deeply was he instructed by Ilúvatar in music. But of the airs and winds Manwë most had pondered, who is the noblest of the Ainur. Of the fabric of Earth had Aulë thought, to whom Ilúvatar had given skin and knowledge scarce less than to Melkor; but the delight and pride of Aulë is in the deed of making, and in the thing made, and neither in possession nor in his own mastery; wherefore he gives and hoards not, and is free from care, passing ever on to some new work.

And Ilúvatar spoke to Ulmo, and said: 'Seest thou not how here in this little realm in the Deeps of Time Melkor hath made war upon thy province? He hath bethought him of bitter cold immoderate, and yet hath not destroyed the beauty of thy fountains, nor of my clear pools. Behold the snow, and the cunning work of frost! Melkor hath devised heats and fire without restraint, and hath not dried up thy desire nor utterly quelled the music of the sea. Behold rather the height and glory of the clouds, and the everchanging mists; and listen to the fall of rain upon the Earth! And in these clouds thou art drawn nearer to Manwë, thy friend, whom thou lovest.'

Then Ulmo answered: 'Truly, Water is become now fairer than my heart imagined, neither had my secret thought conceived the snowflake, nor in all my music was contained the falling of the rain. I will seek Manwë, that he and I may make melodies for ever to my delight!' And Manwë and Ulmo have from the beginning been allied, and in all things have served most faithfully the purpose of Ilúvatar.

But even as Ulmo spoke, and while the Ainur were yet gazing upon this vision, it was taken away and hidden from their sight; and it seemed to them that in that moment they perceived a new thing, Darkness, which they had not known before except in thought. But they had become enamoured of the beauty of the vision and engrossed in the unfolding of the World which came there to being, and their minds were filled with it; for the history was incomplete and the circles of time not full-wrought when the vision was taken away. And some have said that the vision ceased ere the fulfilment of the Dominion of Men and the fading of the Firstborn; wherefore, though the Music is over all, the Valar have not seen as with sight the Later Ages or the ending of the World.

Then there was unrest among the Ainur; but Ilúvatar called to them, and said: 'I know the desire of your minds that what ye have seen should verily be, not only in your thought, but even as ye yourselves are, and yet other. Therefore I say: Eä! Let these things Be! And I will send forth into the Void the Flame Imperishable, and it shall be at the heart of the World, and the World shall Be; and those of you that will may go down into it. And suddenly the Ainur saw afar off a light, as it were a cloud with a living heart of flame; and they knew that this was no vision only, but that Ilúvatar had made a new thing: Eä, the World that Is.

Thus it came to pass that of the Ainur some abode still with Ilúvatar beyond the confines of the World; but others, and among them many of the greatest and most fair, took the leave of Ilúvatar and descended into it. But this condition Ilúvatar made, or it is the necessity of their love, that their power should thenceforward be contained and bounded in the World, to be within it for ever, until it is complete, so that they are its life and it is theirs. And therefore they are named the Valar, the Powers of the World.

But when the Valar entered into Eä they were at first astounded and at a loss, for it was as if naught was yet made which they had seen in vision, and all was but on point to begin and yet unshaped, and it was dark. For the Great Music had been but the growth and flowering of thought in the Tuneless Halls, and the Vision only a foreshowing; but now they had entered in at the beginning of Time, and the Valar perceived that the World had been but foreshadowed and foresung, and they must achieve it. So began their great labours in wastes unmeasured and unexplored, and in ages uncounted and forgotten, until in the Deeps of Time and in the midst of the vast halls of Eä there came to be that hour and that place where was made the habitation of the Children of Ilúvatar. And in this work the chief part was taken by Manwë and Aulë and Ulmo; but Melkor too was there from the first, and he meddled in all that was done, turning it if he might to his own desires and purposes; and he kindled great fires. When therefore Earth was yet young and full of flame Melkor coveted it, and he said to the other Valar: 'This shall be my own kingdom; and I name it unto myself!'

But Manwë was the brother of Melkor in the mind of Ilúvatar, and he was the chief instrument of the second theme that Ilúvatar had raised up against the discord of Melkor; and he called unto himself many spirits both greater and less, and they came down into the fields of Arda and aided Manwë, lest Melkor should hinder the fulfilment of their labour for ever, and Earth should wither ere it flowered. And Manwë said unto Melkor: 'This kingdom thou shalt not take for thine own, wrongfully, for many others have laboured here do less than thou.' And there was strife between Melkor and the other Valar; and for that time Melkor withdrew and departed to other regions and did there what he would; but he did not put the desire of the Kingdom of Arda from his heart.

Now the Valar took to themselves shape and hue; and because they were drawn into the World by love of the Children of Ilúvatar, for whom they hoped, they took shape after that manner which they had beheld in the Vision of Ilúvatar, save only in majesty and splendour. Moreover their shape comes of their knowledge of the visible World, rather than of the World itself; and they need it not, save only as we use raiment, and yet we may be naked and suffer no loss of our being. Therefore the Valar may walk, if they will, unclad, and then even the Eldar cannot clearly perceive them, though they be present. But when they desire to clothe themselves the Valar take upon them forms some as of male and some as of female; for that difference of temper they had even from their beginning, and it is but bodied forth in the choice of each, not made by the choice, even as with us male and female may be shown by the raiment but is not made thereby. But the shapes wherein the Great Ones array themselves are not at all times like to the shapes of the kings and queens of the Children of Ilúvatar; for at times they may clothe themselves in their own thought, made visible in forms of majesty and dread.

And the Valar drew unto them many companions, some less, some well nigh as great as themselves, and they laboured together in the ordering of the Earth and the curbing of its tumults. Then Melkor saw what was done, and that the Valar walked on Earth as powers visible, clad in the raiment of the World, and were lovely and glorious to see, and blissful, and that the Earth was becoming as a garden for their delight, for its turmoils were subdued. His envy grew then the greater within him; and he also took visible form, but because of his mood and the malice that burned in him that form was dark and terrible. And he descended upon Arda in power and majesty greater than any other of the Valar, as a mountain that wades in the sea and has its head above the clouds and is clad in ice and crowned with smoke and fire; and the light of the eyes of Melkor was like a flame that withers with heat and pierces with a deadly cold.