Ring of Ma’rûf works a little differently than the Wishes from others sets. Rather than letting you simply put a card into your hand from outside the game, this ability replaces your next draw. If you wouldn’t draw a card during the rest of the turn, the ability won’t have any effect.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.