Increasing Devotion

You must still follow any timing restrictions and permissions, including those based on the card's type. For instance, you can cast a sorcery using flashback only when you could normally cast a sorcery.

If a card with flashback is put into your graveyard during your turn, you can cast it if it's legal to do so before any other player can take any actions.

A spell cast using flashback will always be exiled afterward, whether it resolves, is countered, or leaves the stack in some other way.