True Revival

You touch a dead creature that you knew in its lifetime. If the creature's soul is free and willing, the creature resurrects with full hit points, free of any conditions, illnesses, or curses. The spell restores their body back to its original form, before the deadly encounter. 

Casting this spell does tax you greatly. Until you finish a long rest, you can’t cast spells again, and you have disadvantage on all attack rolls, ability checks, and saving throws.