Quest for Pure Flame

If the source of the damage is a permanent, Quest for Pure Flame checks whether you control that permanent at the time that damage is dealt. If the permanent has left the battlefield by then, its last known information is used. If the source of the damage is a spell, whether you control it is obvious. If the source of the damage is a card in some other zone (such as a cycled Jund Sojourners), Quest for Pure Flame checks whether you’re the card’s owner, rather than whether you’re its controller.

If a spell causes damage to be dealt, that spell will always identify the source of the damage. In most cases, the source is the spell itself. For example, Lightning Bolt says “Lightning Bolt deals 3 damage to any target.”

If an ability causes damage to be dealt, that ability will always identify the source of the damage. The ability itself is never the source. However, the source of the ability is often the source of the damage. For example, Prodigal Pyromancer’s ability says “Prodigal Pyromancer deals 1 damage to any target.”