The Prophet ﷺ used to wear his ring on his left hand, with the stone facing the inside of his palm.
أن النبي ﷺ كان يتختم في يساره، وكان فصه في باطن كفه.
Abu Dawud narrated it (4227) from Nasr bin Ali, my father told me, Abdul-Aziz bin Abu Rawwad told us, from Nafi, from Ibn Umar, and he mentioned it. Its isnad is hasan because of Abdul-Aziz bin Abu Rawwad, for his hadith is hasan, and Ibn Main deemed him trustworthy.This is supported by the practice of Ibn Umar, for he used to wear his ring on his left hand. Abu Dawud narrated it (4228) with a sahih isnad.The hadiths of both chapters show that wearing the ring on the right hand is permissible, just as wearing it on the left hand is permissible, and there is no dislike in either, except that the right hand is preferable. Perhaps the Prophet ﷺ wore it on the left hand on some occasions to show that this is permissible, and there is nothing irregular about it, as Ibn Hajar said.Nawawi, may Allah have mercy on him, said, "As for the ruling on this matter among the jurists, they agreed on the permissibility of wearing a ring on the right hand, and on its permissibility on the left hand, and there is no dislike in either of them, but they differed over which of the two is preferable. Many of the early generations wore their rings on the right hand, and many on the left. Malik preferred the left hand and disliked the right hand. In our school there are two views among our companions, the sahih view being that the right hand is preferable because it is an adornment, and the right hand is more honorable and more fitting for adornment and honor."Hafiz bin Qayyim said, "The hadiths differ as to whether it was on his right hand or his left hand, but all of them are sahih in terms of isnad." Zad Mad (1/139). And it is as he said, see the hadith that follows.