If an effect says that a player can’t gain life, that player can’t make an exchange such that the player’s life total would become higher; in that case, the exchange won’t happen. Similarly, if an effect redistributes life totals, a player can’t receive a new life total such that the player’s life total would become higher. In addition, a cost that involves having that player gain life can’t be paid, and a replacement effect that would replace a life gain event affecting that player won’t do anything.
May 3, 2019 · War of the Spark
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, they may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that’s waiting to apply, or by a delayed triggered ability that’s waiting to trigger (even if that object is no longer in the zone it used to be in); or a face-up object in the command zone. A source doesn’t need to be capable of dealing damage to be a legal choice. See rule 609.7, “Sources of Damage.”
January 25, 2019 · Ravnica Allegiance
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, they may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that's waiting to apply, or by a delayed triggered ability that's waiting to trigger (even if that object is no longer in the zone it used to be in); or a face-up object in the command zone. A source doesn't need to be capable of dealing damage to be a legal choice. See rule 609.7, "Sources of Damage."
April 27, 2018 · Dominaria
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, they may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that’s waiting to apply, or by a delayed triggered ability that’s waiting to trigger (even if that object is no longer in the zone it used to be in); or a face-up object in the command zone. A source doesn’t need to be capable of dealing damage to be a legal choice. See rule 609.7, “Sources of Damage.”
September 30, 2016 · Kaladesh
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, he or she may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that’s waiting to apply, or by a delayed triggered ability that’s waiting to trigger (even if that object is no longer in the zone it used to be in); or a face-up object in the command zone. A source doesn’t need to be capable of dealing damage to be a legal choice. See rule 609.7, “Sources of Damage.”
May 1, 2014 · Journey into Nyx
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, he or she may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that’s waiting to apply, or by a delayed triggered ability that’s waiting to trigger (even if that object is no longer in the zone it used to be in); or, in certain casual variant games, a face-up card in the command zone. A source doesn’t need to be capable of dealing damage to be a legal choice. See rule 609.7, “Sources of Damage.”
February 1, 2014 · Born of the Gods
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, he or she may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that’s waiting to apply, or by a delayed triggered ability that’s waiting to trigger (even if that object is no longer in the zone it used to be in); or, in certain casual variant games, a face-up card in the command zone. A source doesn’t need to be capable of dealing damage to be a legal choice. See rule 609.7, "Sources of Damage."
September 30, 2011 · Innistrad
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, he or she may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that's waiting to apply, or by a delayed triggered ability that's waiting to trigger (even if that object is no longer in the zone it used to be in); or, in certain casual variant games, a face-up card in the command zone. A source doesn't need to be capable of dealing damage to be a legal choice. See rule 609.7, "Sources of Damage."
June 17, 2011 · Commander 2011
The source of damage is the object that dealt it. If an effect requires a player to choose a source
April 1, 2011 · Duel Decks: Knights vs. Dragons
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, he or she may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that's waiting to apply, or by a delayed triggered ability that's waiting to trigger (even if that object is no longer in the zone it used to be in); or, in certain casual variant games, a face-up card in the command zone. A source doesn't need to be capable of dealing damage to be a legal choice. See rule 609.7, "Sources of Damage."
February 4, 2011 · Mirrodin Besieged
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, he or she may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that’s waiting to apply, or by a delayed triggered ability that’s waiting to trigger (even if that object is no longer in the zone it used to be in); or, in certain casual variant games, a face-up card in the command zone. A source doesn’t need to be capable of dealing damage to be a legal choice. See rule 609.7, “Sources of Damage.”
October 1, 2010 · Scars of Mirrodin
The source of damage is the object that dealt it. If an effect requires a player to choose a source
July 16, 2010 · Magic 2011
The source of damage is the object that dealt it. If an effect requires a player to choose a source of damage, he or she may choose a permanent; a spell on the stack (including a permanent spell); any object referred to by an object on the stack, by a prevention or replacement effect that's waiting to apply, or by a delayed triggered ability that's waiting to trigger (even if that object is no longer in the zone it used to be in); or, in certain casual variant games, a face-up card in the command zone. A source doesn't need to be capable of dealing damage to be a legal choice. See rule 609.7, "Sources of Damage."
February 1, 2010 · Worldwake
Some replacement effects result in multiple card draws. In such a case, any parts of the original event that haven't been replaced by the effect occur first, then the card draws happen one at a time.