Midrasch zu Jeschijahu 9:17

Rabbi Eliezer said: Know thou the power of charity. Come and see from (the instance of) Saul, the son of Kish, who removed the witches and the necromancers from off the earth, and once again he loved that which he had hated. He went to En Dor, to the wife of Zephaniah, the mother of Abner, and he inquired of her for himself by the familiar spirit, and she brought for him Samuel the prophet, and the dead saw Samuel ascending, and they ascended with him, thinking that the resurrection of the dead had come, and the woman beheld, and she became very much confused, as it is said, "And the king said unto her, Be not afraid: for what seest thou?" (1 Sam. 28:13). Some say: Many righteous men like (Samuel) came up with him in that hour.