There are two matters in this question:
A. Who or what was Samuel in 1 Sam 28. That is, does the narrative in 1 Sam 28 really mean that Samuel rose from the dead? In the appendix below, it is shown that the what Saul saw, at the commend of the witch, was not Samuel at all but a demonic delusion. Therefore, Samuel was not raised from the dead.
B. Apart from Samuel, there were others who rose from the dead in the OT such as
- the resurrection of the widow’s son in Zarephath (1 Kings 17:17–22)
- Resurrection of the Shunammite’s son (2 Kings 4:18–37)
- Resurrection of the man thrown into Elisha’s grave (2 Kings 13:20)
So, what is so important about Jesus' resurrection? There are three amazing things about Jesus' resurrection:
- It enabled all other resurrections of everybody else to eternal life, including all saints at the end of time in the Great Resurrection, 1 Cor 15:12-19, John 5:28, 29, 6:54, Dan 12:2. That is, without Jesus' resurrection, there could be no other resurrections to eternal life.
- According to John 2:19-22 and John 10:18, Jesus resurrected Himself from the dead. [Yes, I know, other places say The Father did it, Rom 6:4, Gal 1:1, Eph 1:17-20; and others say the Holy Spirit was also involved, Rom 1:4 & 8:11, 1 Peter 3:18; but that is not to deny that Jesus also did it as well.]
- Jesus' resurrection was qualitatively different from all of the other recorded resurrection in both the OT and the NT. Jesus was raised to eternal life, while all the other recorded resurrections, including Lazarus and the widow's son, later died of old age or other causes.
Thus, the resurrection of Jesus is the central most important doctrine of Christianity because Jesus defeated death (1 Cor 15:50-55) for all people and enabled us to inherit eternal life, 1 John 5:11, 12, John 3:36, 17:3, Titus 1:2, etc.
APPENDIX - Who/What was Samuel in 1 Sam 28?
In answering this question we have at least two possibilities:
- The Samuel that Saul saw was real
If the Samuel that Saul saw was real, ie, a spirit or soul of Samuel in heaven, then,
- according to this chapter, God and heaven are under the earth (See Eccl 12:7) because, the text repeatedly says that Samuel was "brought UP' out of the earth, V8, 10, 11, 13, 14, 15; and the spirit at death returns to God who gave it (Eccl 12:7)
- an illegal witch (Lev 19:31, Deut 18:9-12, Isa 8:19, 29:4) can command the presence of a dead prophet. Necromancy and witchcraft was strictly forbidden in Israel.
- The Samuel that Saul saw was a demonic trick to deceive Saul
By contrast, if what Saul saw was a demonic trick, apparition to deceive him, then Samuel's prophecy is simply stating what was rather obvious - Saul would die in battle the following day.
It did not take divine intelligence to be able to predict this.
Further, according to Jesus, (John 3:13) - "No one has ascended into heaven except the One who descended from heaven—the Son of Man."
Therefore, the second option above is correct - what Saul saw was a demonic trick/apparition to deceive Saul and so was not Samuel at all.