'It is Sunnah. The Messenger of Allah cut off a thief's hand then hung it from his neck."'(Daif)
Sunan an-Nasa'i Book 46, Hadith 112
← Previous Hadith 'I was among the prisoners of Quraizah; we were examined, and whoever had grown (pubic) hair was killed, and whoever had not grown hair, he was allowed to live and was not killed."

Sunan an-Nasa'i Book 46, Hadith 111 Next Hadith → "I said to Fadalah bin 'Ubaid: 'Do you think that hanging the hand from the thief's neck is Sunnah?' He said: 'Yes; a thief was brought to the Messenger of Allah and he cut off his hand and hung it from his neck."' (Daif) Abu 'Abdur-Rahman (An-Nasai) said; Al-Hajjaj bin Artah is weak, his narrations are not used as proof.

Sunan an-Nasa'i Book 46, Hadith 113