Can you cast a spell from exile if it says you may cast it from exile?

Normally, exile is a zone from which you cannot cast spells — cards sitting there are simply out of the game. However, the Comprehensive Rules (CR 601.1, 400.1) recognize that certain effects grant special permission to cast cards from unusual zones, including exile.

When a card or effect explicitly states that you may cast a spell from exile — such as cards with Flashback exiling themselves after use, Suspend removing time counters and letting you cast, or effects like Fblthp exiled by a specific ability — that text creates a specific exception (CR 601.1). The permission is granted by the effect itself, not by the zone alone.

It's important to note that the permission is usually tied to specific conditions. For example, with Suspend (CR 702.62), you may cast the card from exile only when the last time counter is removed. Similarly, cards like Bolas's Citadel grant permission to cast the top card of your library, not anything in exile — the scope is always defined by the granting effect.

Concrete example: You cast Ancestral Vision with Suspend, placing it in exile with 4 time counters. Each upkeep, one counter is removed. When the last counter is removed, you must cast it (the permission and instruction come from the Suspend rule, CR 702.62d). Without that Suspend ability, you could not cast it from exile at all.

So the rule is simple: exile alone grants no casting permission, but if the card or another effect explicitly says you may cast it from exile, that permission is valid and you follow the stated conditions to do so (CR 601.1, 406.3).