§ Of the Voyage of Eärendil and the War of Wrath The Silmarillion

Then Eönwë as herald of the Elder King summoned the Elves of Beleriand to depart from Middle-earth. But Maedhros and Maglor would not hearken, and they prepared, though now with weariness and loathing, to attempt in despair the fulfilment of their oath; for they would have given battle for the Silmarils, were they withheld, even against the victorious host of Valinor, even though they stood alone against all the world. And they sent a message therefore to Eönwë, bidding him yield up now those jewels which of old Fëanor their father made and Morgoth stole from him.