1 Samuel 28:6 And when Saul inquired of the LORD, the LORD answered him not, neither by dreams, nor by Urim, nor by prophets. 7 Then said Saul unto his servants, Seek me a woman that hath a familiar spirit, that I may go to her, and inquire of her. And his servants said to him, Behold, there is a woman that hath a familiar spirit at Endor. 8 And Saul disguised himself, and put on other raiment, and he went, and two men with him, and they came to the woman by night: and he said, I pray thee, divine unto me by the familiar spirit, and bring me him up, whom I shall name unto thee.
Saul inquires to seek out a medium with a familar spirit, even after he commanded them to be put them away. Why did he do this, because he was desperate after God cut himself off from him and eventually slew him for coming against God, 1 Chronicles Chapter 10.
God would not answer Saul neither by dreams, nor by Urim, nor by prophets in whom Samuel was a prophet. The word Urim in vs. 6 means divination as in fortune telling and soothsaying. Saul had to disguise himself so this woman with the familar spirit would not recognize him as she knew how Saul had all mediums and wizards put out of the land.
When Saul, which the woman did not recognize at first, said to call up Samuel she cried with a loud voice when she saw this familar spirit come up taking the form of Samuel and also his voice for this is what familar spirits do as they can take on many forms to deceive us. She cried out as she then knew it was Saul and was afraid he would put her to death for what she had done, but Saul told her not to be afraid.
Even though Saul had asked her to bring up Samuel he never looked at this familar spirit, but had to ask what form is he of. The woman did not say it was Samuel, but only described him as an old man covered with a mantle. Scripture never says that Saul actually looked at this familar spirit, but that when it spoke using the voice of Samuel Saul only knew it to be Samuel by the voice that spoke to him as he stooped with his face to the ground and bowed himself.
This familar spirit used Urim as it looked into the future and told Saul those things we read in 1 Chronicles 10. This is why Saul was so afraid because of the words this familar spirit spoke to him that he fell straightway having no strength to even stand.
God did not bring up Samuel from the grave to foretell Saul's future as again it states in vs. 6 the LORD answered him not, neither by dreams, nor by Urim, nor by prophets.
1 Chronicles 10:13 So Saul died for his transgression which he committed against the LORD, even against the word of the LORD, which he kept not, and also for asking counsel of one that had a familiar spirit, to inquire of it; 14 And inquired not of the LORD: therefore he slew him, and turned the kingdom unto David the son of Jesse.