Then said Saul unto his servants, Seek me a woman that hath a familiar spirit, that I may go to her, and enquire of her. And his servants said to him, Behold, there is a woman that hath a familiar spirit at Endor. (1 Samuel 28:7)
The witch of Endor had made agreement with Satan to follow his directions in all things; and he would perform wonders and miracles for her, and would reveal to her the most secret things, if she would yield herself unreservedly to be controlled by his Satanic majesty. This she had done (The Spirit of Prophecy 1:375, 376).