Gideon's Triumph — ruling 1

Gideon’s Triumph can be cast before combat damage has been dealt. In this case, it can be cast before or after blockers have been chosen.

Gideon's Triumph — ruling 2

Gideon’s Triumph can be cast after combat damage has been dealt. In this case, the target player chooses one or two creatures that attacked or blocked this turn and have survived combat damage.

Gideon's Triumph — ruling 3

A creature that was put onto the battlefield attacking didn’t attack, so it can’t be sacrificed.

Gideon's Triumph — ruling 4

A creature that attacked and was removed from combat (such as by Spires of Orazca) still attacked, so it can be sacrificed.

Gideon's Triumph — ruling 5

Gideon’s Triumph targets the player, not the creature or creatures to be sacrificed. A creature with hexproof may be sacrificed this way.

Gideon's Triumph — ruling 6

Whether you control an appropriate planeswalker is checked only as the spell resolves.

Gideon's Triumph — ruling 7

Controlling more than one planeswalker of the appropriate type won’t have any more of a benefit than just controlling one.

Gideon's Triumph : règles, fonctionnement et interactions (MTG)

Gideon's Triumph 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

Target opponent sacrifices a creature of their choice that attacked or blocked this turn. If you control a Gideon planeswalker, that player sacrifices two of those creatures of their choice instead.

How it works : Gideon's Triumph

Original English text — Wizards of the Coast / Scryfall

#1May 3, 2019· Wizards of the Coast
Gideon’s Triumph can be cast before combat damage has been dealt. In this case, it can be cast before or after blockers have been chosen.
No other card is named in this ruling.
#2May 3, 2019· Wizards of the Coast
Gideon’s Triumph can be cast after combat damage has been dealt. In this case, the target player chooses one or two creatures that attacked or blocked this turn and have survived combat damage.
No other card is named in this ruling.
#3May 3, 2019· Wizards of the Coast
A creature that was put onto the battlefield attacking didn’t attack, so it can’t be sacrificed.
No other card is named in this ruling.
#4May 3, 2019· Wizards of the Coast
A creature that attacked and was removed from combat (such as by Spires of Orazca) still attacked, so it can be sacrificed.
No other card is named in this ruling.
#5May 3, 2019· Wizards of the Coast
Gideon’s Triumph targets the player, not the creature or creatures to be sacrificed. A creature with hexproof may be sacrificed this way.
No other card is named in this ruling.
#6May 3, 2019· Wizards of the Coast
Whether you control an appropriate planeswalker is checked only as the spell resolves.
No other card is named in this ruling.
#7May 3, 2019· Wizards of the Coast
Controlling more than one planeswalker of the appropriate type won’t have any more of a benefit than just controlling one.
No other card is named in this ruling.