The ruling on men wearing rings. And the wisdom behind the Prophet (peace and blessings be upon him) adopting a ring.

The Shaykh : Wearing a ring is not among the recommended practices; rather, it is among the matters that are done when there is a need for them, and otherwise they are not done. This is evidenced by the fact that the Messenger (peace and blessings be upon him) did not wear a ring, but when it was said to him that the kings and leaders to whom he writes do not accept a letter unless it is sealed, he adopted a ring and engraved "Muhammad, Messenger of Allah" on its stone, so that when he finished a letter, he would seal it with this ring.