Its Shirk to Wear Rings or Threads or the Like as a Means of Prevention or Lifting of Afflictions:
Allaah , says:
...
" Say: "Tell me then, the things that you invoke besides Allaah - if Allaah intended some harm to me, could they remove His harm, or if He intended some mercy for me, could they withhold His Mercy?" Say: "Sufficient for me is Allaah; in Him those who trust [the true Believers] must put their trust."" (Qur'an 39:38)
In this verse, Allaah , Most Glorified, Most High commands His Prophet, Muhammad (SAWS) to reject those powerless, graven images worshipped by the polytheists, which can neither remove any harm which might befall a person by Allah's Decree, nor prevent any sustenance or blessings which might come to a person from Him. Then He commands him to place his trust in Allaah , for He is Sufficient to bring benefit or prevent harm for all who sincerely depend upon Him.
Relevance of This Verse to the Subject
That it proves that protection from harm is only from Allaah , and so entrusting oneself to any other protector - such as rings, threads etc. is an act of Shirk.
It is reported on the authority of Umran Ibn Husain (Son of Husain (R A)), that Allaah's Messenger (SAWS) saw a man with a brass ring in his hand, and he asked him: "What is this?" He replied: "It is for protection from al-waahinah(rheumatism)". The Prophet (SAWS) answered:
"Remove it at once, for verily, it will not increase you except in weakness, and were you to die whilst wearing it, you would never be successful." (Narrated by Ahmad, with an acceptable Sanad)
This hadith informs us that the Prophet (SAWS) saw a man with a brass ring in his hand, and he asked him for what purpose he was wearing it. The man answered that he was wearing it to protect him from illness, at which the Prophet (SAWS) ordered him to remove it and informed him that it would only cause him to become weak and not protect him from illness at all, and that should he die while wearing it and believing in its power to protect him, he would not succeed in the Hereafter, nor would he know eternal bliss.
It is reported by Ibn Abi Hatim, on the authority of Huzaifah (R A) that he saw a man with a thread in his hand to protect him from fever; he broke it and recited the Words of Allaah (SWT), Most High:
" And most of them do not believe in Allaah, except that they associate partners with Him" (Qur'an 12:106)
Conclusion:
This proves that wearing an amulet or talisman, believing that it can benefit one is an act of Shirk because benefits come only from Allaah , the Almighty, the All-powerful.
The use of threads as protection from harm is an act of Shirk, because protection from harm comes only from Allaah , the Almighty, the All-powerful.