Sahih Muslim 2095
Sahih Muslim · Book 37: The Book of Clothes and Adornment · Wearing Rings On The Little Finger
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 .
Anas reported that the ring of Allah's Apostle (ﷺ) was on this, and he pointed toward the little finger of his left hand.