Teferi's Protection 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

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.) Exile Teferi's Protection.

Complete guide

Teferi's Protection is one of the most powerful defensive tools in Magic: The Gathering, offering a way to vanish from the game entirely until your next turn. By combining phasing and protection, it shields both your life total and your board from almost any threat. Mastering this spell requires understanding how to navigate a world where your permanents temporarily cease to exist.

Total Fortification

When Teferi's Protection resolves, three major effects occur. First, your life total becomes locked; it cannot increase or decrease through any means. Second, you gain protection from everything, meaning you can't be targeted, damaged, or enchanted. Finally, every permanent you control phases out, making them impossible to interact with as they are treated as though they don't exist.

The Mechanics of Phasing

Phasing is unique because it doesn't cause permanents to leave the battlefield. This means 'enters the battlefield' or 'leaves the battlefield' abilities will not trigger. Your permanents, along with any Auras or Equipment attached to them, simply step out of time. They will automatically phase back in just before you untap during your next untap step, retaining any counters or choices made when they were originally played.

Life and Costs

While your life total can't change, you are barred from paying any costs that require life, such as the activation cost of a fetch land or a black spell's additional cost. Furthermore, if an effect would replace life gain or loss with another event, that replacement effect fails because the underlying life change is impossible. However, damage can still be dealt to you if an effect says 'damage can't be prevented'; in that case, your life total still won't move, but secondary effects like Infect or Lifelink will still function.

Strategic Timing

The best time to cast this spell is in response to a 'board wipe' or a lethal attack. Since the spell exiles itself upon resolution, it is a one-time escape hatch. Note that if you somehow skip your next untap step, your permanents will remain phased out until you actually have an untap step, even though your protection and life-locking effects will have expired.

Interaction examples

Evading Targeted Removal

Generous Gift

If an opponent casts Generous Gift targeting one of your lands, you can cast Teferi's Protection in response. As Teferi's Protection resolves, your land phases out. When Generous Gift tries to resolve, it checks its target and finds it no longer exists on the battlefield. The spell is then removed from the stack with no effect; you keep your land and the opponent does not provide you with an Elephant token.

Choosing the Best Shield

Flawless Maneuver

Imagine an opponent casts a spell that gives all creatures -5/-5. While Flawless Maneuver would grant your creatures indestructible, it wouldn't save them from having zero toughness. In this scenario, Teferi's Protection is the superior choice. By phasing your creatures out, they are no longer on the battlefield to be affected by the stat reduction, ensuring they return safely on your next turn.

Guide written with AI from the official text and rulings. Official English text prevails.