Exile the top seven cards of your library. Until end of turn, you may cast spells from among them. If this spell was cast from your hand, add ten mana of any one color.
2018-07-13
Any cards not cast, including land cards, remain in exile.
2018-07-13
Apex of Power doesn't change when you can cast the exiled cards. For example, if you exile a sorcery card, you can cast it only during your main phase when the stack is empty.
2018-07-13
Casting an exiled card causes it to leave exile. You can't cast it multiple times.
2018-07-13
If an effect copies Apex of Power, the copy wasn't cast at all, so you won't add ten mana.