Sunan an-Nasa'i, Hadith 5211 ⓘ
It was narrated that 'Ali said: "The Messenger of Allah [SAW] forbade me to wear a ring on this one and this one," meaning the forefinger and middle finger. And this is the wording of Ibn Al-Muthanna.
أَخْبَرَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَمُحَمَّدُ بْنُ بَشَّارٍ، قَالاَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ، عَنْ سُفْيَانَ، عَنْ عَاصِمِ بْنِ كُلَيْبٍ، عَنْ أَبِي بُرْدَةَ، عَنْ عَلِيٍّ، قَالَ نَهَانِي رَسُولُ اللَّهِ صلى الله عليه وسلم عَنِ الْخَاتَمِ فِي هَذِهِ وَهَذِهِ . يَعْنِي السَّبَّابَةَ وَالْوُسْطَى . وَاللَّفْظُ لاِبْنِ الْمُثَنَّى .
also referenced under: Book 48, Hadith 172 (In-Book) & Volume 6, Book 48, Hadith 5214 (DarusSalam)