The Silmarillion

Then Melkor lusted for the Silmarils, and the very memory of their radiance was a gnawing fire in his heart. From that time forth, inflamed by this desire, he sought ever more eagerly how he should destroy Fëanor and end the friendship of the Valar and the Elves; but he dissembled his purposes with cunning, and nothing of his malice could yet be seen in the semblance that he wore. Long was he at work, and slow at first and barren was his labour. But he that sows lies in the end shall not lack of a harvest, and soon he may rest from toil indeed while others reap and sow in his stead. Ever Melkor found some ears that would heed him, and some tongues that would enlarge what they had heard; and his lies passed from friend to friend, as secrets of which the knowledge proves the teller wise. Bitterly did the Noldor atone for the folly of their open ears in the days that followed after.

When he saw that many leaned towards him, Melkor would often walk among them, and amid his fair words others were woven, so subtly that many who heard them believed in recollection that they arose from their own thought. Visions he would conjure in their hearts of the mighty realms that they could have ruled at their own will, in power and freedom in the East; and then whispers went abroad that the Valar had brought the Eldar to Aman because of their jealousy, fearing that the beauty of the Quendi and the makers' power that Ilúvatar had bequeathed to them would grow too great for the Valar to govern, as the Elves waxed and spread over the wide lands of the world.

In those days, moreover, though the Valar knew indeed of the coming of Men that were to be, the Elves as yet knew naught of it; for Manwë had not revealed it to them. Bat Melkor spoke to them in secret of Mortal Men, seeing how the silence of the Valar might be twisted to evil. Little he knew yet concerning Men, for engrossed with his own thought in the Music he had paid small heed to the Third Theme of Ilúvatar; but now the whisper went among the Elves that Manwë held them captive, so that Men might come and supplant them in the kingdoms of Middle-earth, for the Valar saw that they might more easily sway this short-lived and weaker race, defrauding the Elves of the inheritance of Ilúvatar. Small truth was there in this, and little have the Valar ever prevailed to sway the wills of Men; but many of the Noldor believed, or half believed, the evil words.

Thus ere the Valar were aware, the peace of Valinor was poisoned. The Noldor began to murmur against them, and many became filled with pride, forgetting how much of what they had and knew came to them in gift from the Valar. Fiercest burned the new flame of desire for freedom and wider realms in the eager heart of Fëanor; and Melkor laughed in his secrecy, for to that mark his lies had been addressed, hating Fëanor above all, and lusting ever for the Silmarils. But these he was not suffered to approach; for though at great feasts Fëanor would wear them, blazing on his brow, at other times they were guarded close, locked in the deep chambers of his hoard in Tirion. For Fëanor began to love the Silmarils with a greedy love, and grudged the sight of them to all save to his father and his seven sons; he seldom remembered now that the light within them was not his own.

High princes were Fëanor and Fingolfin, the elder sons of Finwë, honoured by all in Aman; but now they grew proud and jealous each of his rights and his possessions. Then Melkor set new lies abroad in Eldamar, and whispers came to Fëanor that Fingolfin and his sons were plotting to usurp the leadership of Finwë and of the elder line of Fëanor, and to supplant them by the leave of the Valar; for the Valar were ill-pleased that the Silmarils lay in Tirion and were not committed to their keeping. But to Fingolfin and Finarfin it was said: 'Beware! Small love has the proud son of Míriel ever had for the children of Indis. Now he has become great, and he has his father in his hand. It will not be long before he drives you forth from Túna!'

And when Melkor saw that these lies were smouldering, and that pride and anger were awake among the Noldor, he spoke to them concerning weapons; and in that time the Noldor began the smithying of swords and axes and spears. Shields also they made displaying the tokens of many houses and kindreds that vied one with another; and these only they wore abroad, and of other weapons they did not speak, for each believed that he alone had received the warning. And Fëanor made a secret forge, of which not even Melkor was aware; and there he tempered fell swords for himself and for his sons, and made tall helms with plumes of red. Bitterly did Mahtan rue the day when he taught to the husband of Nerdanel all the lore of metalwork that he had learned of Aulë.