Eminent Spellcaster (Mythic)

You can sacrifice your highest level spells to cast divine spells beyond your normal capacity. 

Prerequisite: Cleric 17, Inquisitor 19, Oracle 18, or Warpriest 19.  

Benefits: Once per month, you can sacrifice access to your highest level of spells for 1 day to cast a single Divine Eminence spell associated with your deity's blessings, domains, inquisitions, or mysteries. 
You may also choose to cast the Divine Eminence spell granted by the All Sphere, regardless of your deity's granted blessings, domains, inquisitions, or mysteries. For example, a cleric with a deity that grants access to the Chaos, Destruction, and War spheres can sacrifice his 9th level spells for the day to cast either Beast of Destruction (Destruction Sphere), Mythic Quest (All Sphere), Planar Army (Chaos Sphere), or War Band (War Sphere).