Sahih Muslim , Book 24, Hadith 5225 (USC-MSA) ⓘ
Anas reported that the ring of Allah's Apostle was on this, and he pointed toward the little finger of his left hand.
وَحَدَّثَنِي أَبُو بَكْرِ بْنُ خَلاَّدٍ الْبَاهِلِيُّ، حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، حَدَّثَنَا حَمَّادُ، بْنُ سَلَمَةَ عَنْ ثَابِتٍ، عَنْ أَنَسٍ، قَالَ كَانَ خَاتِمُ النَّبِيِّ صلى الله عليه وسلم فِي هَذِهِ . وَأَشَارَ إِلَى الْخِنْصَرِ مِنْ يَدِهِ الْيُسْرَى .
also referenced under: Book 37, Hadith 104 (In-Book) & Hadith 2095 (Reference)