Why did he ask her his appearance?
Rashi (from Vayikra Rabah 26:7): The Ba'alas Ov sees the one raised, but does not hear. The asker hears a low voice, but does not see the one who speaks. Radak (24, citing this Midrash) - one who does not need it, e.g. Avner and Amasha, do not hear or see him.
Why was he wearing a robe?
Rashi: His mother made it for him (2:19). He grew in it 1 , was buried in it, and came up in it (Tanchuma Emor 2/4). In the future, the dead will be revived in their garments.
Radak: He used to wear a robe. This is how Sha'ul knew that it is Shmuel!
Sichos Musar (5732, 5): Why was this miracle needed? Are there not enough robes in the world?! She made it amidst love, tears, Tefilos and all her heart. With every stitch she prayed that he spread Torah. When he wore it, love of Yisrael and of Hashem entered him.
How could a witch have power over the soul of a Navi clinging to Hashem after his death?
Ralbag: It is all based on Dimyon. 1
R. Shmuel bar Chofni Gaon (cited in Radak (24) and briefly in Malbim 12). All actions of an Ov are folly. 2 All Ge'onim hold like this. The Ba'alas Ov brings a man who speaks in a low voice from a hiding place. Refer to 28:12:1:2. When Sha'ul came to ask from her, she knew that Yisrael will go to war tomorrow, and they were afraid. She told the man in hiding what to say; it was known that Sha'ul ordered to kill Kohanei Nov. 3 The verses call [the one who talked] "Shmuel", for so Sha'ul thought. It was known that Sha'ul's kingship was lost due to Amalek, and it was given to David. Even though the Gemara implies that it was truly Shmuel, intellect refutes this.
Rav Hai Gaon and Rav Sadya Gaon (cited in Radak (24) and briefly in Malbim 12): It is unreasonable that she would know the future, or be able to return Shmuel to life. Rather, Hashem revived him, so Sha'ul will know what will happen to him and his house. She was astounded at this, and screamed loudly. She asked Sha'ul whom he wants to talk to, with intent to do her usual folly. 4
Malbim (12 citing Mahari): A demon took the form of Shmuel. He is called Shmuel due to his appearance.
Malbim (12 citing Akeidas Yitzchak): She began the process, and through this Shmuel himself was aroused to come; he was not forced.
Malbim (12): Chachamim said that Ov has the power to raise the dead from their graves. They said that for a commoner, his feet rise first. This was known in their days. After a person dies, his Neshamah returns to Hashem who gave it, but the Nefesh that is connected to the body does not depart until the body rots in the grave after 12 months. All 12 months it ascends and descends (Shabbos 152b), due to its connection to the body. During this time, Ov can rule over the Ru'ach, and it can tell the future through witchcraft. The Neshamah stays in its place above.
It seems that Malbim (12) understood that Dimyon is imagination, for he rejects this together with the opinion that the entire matter is folly. Refer to 28:14:3:2*. Perhaps Ralbag calls Dimyon thoughts that are not based on something physical. (PF)
Malbim: This cannot be! The Ov led to a Nevu'ah of what will be tomorrow, and who will be the next king! (The Gaon said that it was known that Sha'ul's kingship was given to David! However, why would Sha'ul lower himself to engage in folly?! - PF)
Why did Radak say so? 'Shmuel' did not mention this!
Radak, Malbim: If Hashem revived a Mes in order to inform Sha'ul of the future, why did he not answer him via the Urim v'Tumim or Nevi'im, rather, via a Ba'alas Ov? (Perhaps the Urim did not answer him because he killed the Kohanim, and a Navi would fear to tell him that David will be king, just like Shmuel feared lest Sha'ul know that he anoints David. - PF) Sha'ul was a Chacham and king, and he had Chachamim with him. Did they not know that it is folly?! Rather, it is like we explained (refer to 28:3:4:1-3, 28:14:3:6).
