Disclaimer: Of course I do not own The Silmarillion. Mr Tolkien does. I just borrow them from time to time and do my best to treat them nicely.
Lay of Maedhros
Light unsullied tethered my eyes
Caught in jewels of yore it shone
In Eldamar the Elvenhome
In crystal halls of Tirion
Radiance of Varda's stars,
Silver dew and golden rain,
Fate of world, of Arda Marred
Lies locked within the hallowed gems
On Hither Shore long I roamed
Destitute of rest and joy
For more than lands, than lore and might
My heart desired stolen Light
Forever burning in my mind
Stirring hatred terrible
Bond stronger than Aulë's chains -
Dreadful vow, the Oath unbreakable
I stand before the belching abyss,
Alone, condemned.
Thrice doom played me:
Born of Fire, fire-scorched,
And end I'll meet in flaming jaws
For Light I claimed but darkness veiled me
And Light devours this hand blood-stained
Hope I clung to is forlorn
Blind I strayed with spirit quailing
Vain is the Oath, my right is void
And all repentance unavailing
To make a few things clear:
-Born of Fire... -It isn't hard to guess Maedhros was speaking of Fëanor, his father
-Vain is the Oath, my right is void -This is from The Silmarillion. It is said there that Maedhros and Maglor sent message to Eonwë after The Great Battle, bidding him surrender the Silmarills, but he declared their right void because of their deeds. And when he finally took the Silmaril in his hand Maedhros realized Eonwë's words were true.