FOR the Ring yearns above all else to return to the hand of its master.
Hello. In The Lord of the Rings - The Fellowship of the Ring (2001), Gandalf says:
"Sauron needs only this Ring to cover all the lands in a second darkness. He is seeking it. All his thought is bent on it. FOR the Ring yearns above all else to return to the hand of its master. They are one, the Ring and the Dark Lord. "

I understand that the conjunction for means "because" here, but what I don't understand is that why he used it. Is it called for at all? It just that I don't see how the sentence " FOR the Ring yearns above all else to return to the hand of its master." explains "All his thought is bent on it" or any other sentence that comes before it. So I wonder if you could tell me whether we can justify the use of this for here.

Thank you.

Question

FOR the Ring yearns above all else to return to the hand of its master.
Hello. In The Lord of the Rings - The Fellowship of the Ring (2001), Gandalf says: 
"Sauron needs only this Ring to cover all the lands in a second darkness. He is seeking it. All his thought is bent on it. FOR the Ring yearns above all else to return to the hand of its master. They are one, the Ring and the Dark Lord. "

I understand that the conjunction for means "because" here, but what I don't understand is that why he used it. Is it called for at all? It just that I don't see how the sentence " FOR the Ring yearns above all else to return to the hand of its master." explains "All his thought is bent on it" or any other sentence that comes before it. So I wonder if you could tell me whether we can justify the use of this for here.

Thank you.

Answer

Good point.  The ring’s yearning does not seem to explain why Sauron is obsessed with the ring — he presumably would be obsessed even if the ring itself had no will of its own.  One possible explanation:  Tolkien loves to use language that imparts an archaic tone, and starting a sentence with “For” imparts such a tone.  But if I had to defend the use of “For” here in the sense of “because”, the best explanation I can think of concerns the sentence that follows (regarding the Ring and the Dark Lord being one):  If part of YOU were calling out to you, yearning to rejoin you, wouldn’t your thoughts be focused on that missing part?  So, your thoughts focus on the thing BECAUSE the thing is calling out to you.

Answer

"Sauron needs only this Ring to cover all the lands in thesecond darkness. He is seeking it. All his thoughts are bent on it. For the Ring yearns above all else to return to the hand of its Master. They are one, the Ring and the Dark Lord. "

Answer

Sauron is seeking the ring because that is the "only" thing he needs to cover all the lands in a second darkness. He is obsessed with doing so. The "magical?" ring yearns to return to the hand of Sauron, (if Sauron is the master). If Sauron is not the master then for Sauron to possess it would give Sauron great power.  They are one the ring and the dark master, seems to be suggesting that whoever wears the ring is or shall become the dark master. Unfortunately I am not a fan of Tolkien or "the lord of the rings". If I were and had seen the film or read the book I could give a better explanation for you. Very often much more preceding context is needed to answer questions on italki.

Answer

It can be left out.  The language used in"The Lord of The Rings" is not modern english.