Out of desperation, Saul inquires of the witch of Endor for revelation.

1 Samuel 28:3–14

3 Now Samuel was dead, and all Israel had lamented him, and buried him in Ramah, even in his own city. And Saul had put away those that had familiar spirits, and the wizards, out of the land.
4 And the Philistines gathered themselves together, and came and pitched in Shunem: and Saul gathered all Israel together, and they pitched in Gilboa.
5 And when Saul saw the host of the Philistines, he was afraid, and his heart greatly trembled.
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 En-dor.
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.
9 And the woman said unto him, Behold, thou knowest what Saul hath done, how he hath cut off those that have familiar spirits, and the wizards, out of the land: wherefore then layest thou a snare for my life, to cause me to die?
10 And Saul sware to her by the Lord, saying, As the Lord liveth, there shall no punishment happen to thee for this thing.
11 Then said the woman, Whom shall I bring up unto thee? And he said, Bring me up Samuel.
12 And when the woman saw Samuel, she cried with a loud voice: and the woman spake to Saul, saying, Why hast thou deceived me? for thou art Saul.
13 And the king said unto her, Be not afraid: for what sawest thou? And the woman said unto Saul, I saw gods ascending out of the earth.
14 And he said unto her, What form is he of? And she said, An old man cometh up; and he is covered with a mantle. And Saul perceived that it was Samuel, and he stooped with his face to the ground, and bowed himself.

Elder Bruce R. McConkie wrote:

“Those religionists who attempt and frequently attain communion (as they suppose) with departed spirits are called spiritualists. Their doctrine and belief that mediums and other mortals can actually hold intercourse with the spirits of the dead is called spiritualism. Such communion, if and when it occurs, is manifest by means of physical phenomena, such as so-called spirit-rappings, or during abnormal mental states, such as in trances. These communions are commonly arranged and shown forth through the instrumentality of mediums. . . .

“. . . No matter how sincerely mediums may be deceived into thinking they are following a divinely approved pattern, they are in fact turning to an evil source ‘for the living to hear from the dead.’ Those who are truly spiritually inclined know this by personal revelation from the true Spirit; further, the information revealed from spirits through mediums is not according to ‘the law and to the testimony.’ . . .

“. . . In ancient Israel, spiritualistic practices were punishable by death. ‘A man also or woman that hath a familiar spirit, or that is a wizard, shall surely be put to death’ (Leviticus 20:27Exodus 22:18).”

(Mormon Doctrine, 2nd ed. [1966], 759–60.)