Punishing Fire — ruling 1

Punishing Fire's triggered ability triggers only if it's already in your graveyard at the time an opponent gains life. For example, you can cast it in response to a spell or ability that will cause an opponent to gain life. In that case, Punishing Fire will resolve first, so it will be in the graveyard by the time the opponent gains life. However, if you wait until an opponent actually gains life and then cast Punishing Fire, you won't be able to return it to your hand at that time.

Punishing Fire — ruling 2

You choose whether to pay {R} as the triggered ability resolves.

Punishing Fire — ruling 3

If Punishing Fire has left your graveyard by the time its triggered ability resolves, you may still pay {R}, but you won't return it to your hand. This is true even if Punishing Fire has left your graveyard and returned to it by the time its triggered ability resolves.

Punishing Fire : règles, fonctionnement et interactions (MTG)

Punishing Fire is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Punishing Fire deals 2 damage to any target. Whenever an opponent gains life, you may pay . If you do, return this card from your graveyard to your hand.

How it works : Punishing Fire

Original English text — Wizards of the Coast / Scryfall

#1October 1, 2009· Wizards of the Coast
Punishing Fire's triggered ability triggers only if it's already in your graveyard at the time an opponent gains life. For example, you can cast it in response to a spell or ability that will cause an opponent to gain life. In that case, Punishing Fire will resolve first, so it will be in the graveyard by the time the opponent gains life. However, if you wait until an opponent actually gains life and then cast Punishing Fire, you won't be able to return it to your hand at that time.
No other card is named in this ruling.
#2October 1, 2009· Wizards of the Coast
You choose whether to pay as the triggered ability resolves.
No other card is named in this ruling.
#3October 1, 2009· Wizards of the Coast
If Punishing Fire has left your graveyard by the time its triggered ability resolves, you may still pay , but you won't return it to your hand. This is true even if Punishing Fire has left your graveyard and returned to it by the time its triggered ability resolves.
No other card is named in this ruling.