Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, scry 1. (Look at the top card of your library. You may put that card on the bottom of your library.)
If there are additional costs to cast an instant or sorcery spell, apply those before applying cost reductions.
Jace’s Sanctum can reduce alternative costs such as miracle or overload costs.
Jace’s Sanctum’s scry ability will resolve before the instant or sorcery spell that caused it to trigger.
The first ability of Jace’s Sanctum can’t reduce the colored mana requirement of an instant or sorcery spell.