Sunan an-Nasai 20032
In-book no 5296أَخْبَرَنَا هَنَّادُ بْنُ السَّرِيِّ، عَنْ أَبِي الأَحْوَصِ، عَنْ عَاصِمِ بْنِ كُلَيْبٍ، عَنْ أَبِي بُرْدَةَ، عَنْ عَلِيٍّ، قَالَ نَهَانِي رَسُولُ اللَّهِ صلى الله عليه وسلم أَنْ أَلْبَسَ فِي إِصْبَعِي هَذِهِ وَفِي الْوُسْطَى وَالَّتِي تَلِيهَا .
It was narrated that 'Ali said: "The Messenger of Allah forbade me to wear (a ring) on this finger," and it was on the middle finger and the one next to it.