Oath of Mages

Oracle Text

At the beginning of each player's upkeep, that player chooses target player who has more life than they do and is their opponent. The first player may have Oath of Mages deal 1 damage to the second player.

Card Rulings

10/1/2009 The ability can only target an opponent of the current player.
10/1/2009 The targeted player having more life than the current player is a part of the targeting requirement. A player can’t be targeted by this ability unless it’s true, and the ability doesn’t resolve if it’s no longer true at that time.