Martyr's Soul — ruling 1

When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Convoke applies after the total cost is calculated. Convoke doesn't change a spell's mana cost or mana value.

Martyr's Soul — ruling 2

You can tap any untapped creature you control to convoke a spell, even one you haven't controlled continuously since the beginning of your most recent turn.

Martyr's Soul — ruling 3

Tapping an untapped creature that's attacking or blocking to convoke a spell won't cause that creature to stop attacking or blocking.

Martyr's Soul — ruling 4

Tapping a multicolored creature using convoke will pay for {1} or one mana of your choice of any of that creature's colors.

Martyr's Soul — ruling 5

If a creature you control has a mana ability with {T} in the cost, activating that ability while casting a spell with convoke will result in the creature being tapped before you pay the spell's costs. You won't be able to tap it again for convoke. Similarly, if you sacrifice a creature to activate a mana ability while casting a spell with convoke, that creature won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for convoke.

Martyr's Soul — ruling 6

Because convoke isn't an alternative cost, it can be used in conjunction with alternative costs.

Martyr's Soul — ruling 7

If you control any tapped lands as Martyr's Soul enters the battlefield, its last ability doesn't trigger at all. If you control any tapped lands as the ability resolves, you won't put two +1/+1 counters on Martyr's Soul.

Martyr's Soul : règles, fonctionnement et interactions (MTG)

Martyr's Soul 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

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.) When this creature enters, if you control no tapped lands, put two +1/+1 counters on it.

How it works : Martyr's Soul

Original English text — Wizards of the Coast / Scryfall

#1January 12, 2024· Wizards of the Coast
When calculating a spell's total cost, include any alternative costs, additional costs, or anything else that increases or reduces the cost to cast the spell. Convoke applies after the total cost is calculated. Convoke doesn't change a spell's mana cost or mana value.
No other card is named in this ruling.
#2January 12, 2024· Wizards of the Coast
You can tap any untapped creature you control to convoke a spell, even one you haven't controlled continuously since the beginning of your most recent turn.
No other card is named in this ruling.
#3January 12, 2024· Wizards of the Coast
Tapping an untapped creature that's attacking or blocking to convoke a spell won't cause that creature to stop attacking or blocking.
No other card is named in this ruling.
#4January 12, 2024· Wizards of the Coast
Tapping a multicolored creature using convoke will pay for or one mana of your choice of any of that creature's colors.
No other card is named in this ruling.
#5January 12, 2024· Wizards of the Coast
If a creature you control has a mana ability with in the cost, activating that ability while casting a spell with convoke will result in the creature being tapped before you pay the spell's costs. You won't be able to tap it again for convoke. Similarly, if you sacrifice a creature to activate a mana ability while casting a spell with convoke, that creature won't be on the battlefield when you pay the spell's costs, so you won't be able to tap it for convoke.
No other card is named in this ruling.
#6January 12, 2024· Wizards of the Coast
Because convoke isn't an alternative cost, it can be used in conjunction with alternative costs.
No other card is named in this ruling.
#7June 14, 2019· Wizards of the Coast
If you control any tapped lands as Martyr's Soul enters the battlefield, its last ability doesn't trigger at all. If you control any tapped lands as the ability resolves, you won't put two +1/+1 counters on Martyr's Soul.
No other card is named in this ruling.