Historical Rules · 17 July 2015
Rule 601.2
Official source text from the 17 July 2015 Rules release
To cast a spell is to take it from where it is (usually the hand), put it on the stack, and pay its costs, so that it will eventually resolve and have its effect. Casting a spell includes proposal of the spell (rules 601.2a–e) and determination and payment of costs (rules 601.2f–h). To cast a spell, a player follows the steps listed below, in order. If, at any point during the casting of a spell, a player is unable to comply with any of the steps listed below, the casting of the spell is illegal; the game returns to the moment before the casting of that spell was proposed (see rule 717, “Handling Illegal Actions”).