MTG Keyword Rules — Comprehensive Rules Glossary

To reveal a card, show that card to all players for a brief time. If an effect causes a card to be revealed, it remains revealed for as long as necessary to complete the parts of the effect that card is relevant to. If the cost to cast a spell or activate an ability includes revealing a card, or if a card is revealed because an ability is activated from a hidden zone (see rule 602.2a), the card remains revealed from the time the spell or ability is announced until the time it leaves the stack. If revealing a card causes a triggered ability to trigger, the card remains revealed until that triggered ability leaves the stack. If that ability isn’t put onto the stack the next time a player would receive priority, the card ceases to be revealed.

Revealing a card doesn’t cause it to leave the zone it’s in.

A card that is currently revealed may be revealed again. Example: Telepathy is an enchantment card that reads “Your opponents play with their hands revealed.” Silvergill Adept is a creature card that reads, in part, “As an additional cost to cast this spell, reveal a Merfolk card from your hand or pay {3}.” A player may reveal a Merfolk card from their hand to pay the additional cost of Silvergill Adept even if that card is already revealed due to Telepathy’s effect.

If cards in a player’s library are shuffled or otherwise reordered, any revealed cards that are reordered stop being revealed and become new objects.

Some effects instruct a player to look at one or more cards. Looking at a card follows the same rules as revealing a card, except that the card is shown only to the specified player.