Spock
Alabama had it right: you can't keep a good Vulcan down.
Spock was easily Star Trek's most popular character—sorry, Kirk—and his death had a huge impact in The Wrath of Khan, the supposed end of the franchise. But when Paramount decided to make another film, they had to find a way to bring Spock back into the fold. Because popularity equals profits, and profits equals…more profits?
But how do you keep a character you just killed off? Simple. Make him a Space Christ Figure.
Father, Son, Holy Spock
The allusions highlighting Spock as a Christ Figure start early. During the film's opening credits, the camera pans over Spock's burial tube, and we can clearly see it's labeled "Mark VI."
Mark VI is a reference to the Biblical Gospel of Mark. Specifically, it refers to the chapter featuring the Death of John the Baptist. John the Baptist was an important figure in the Gospel. In Biblical tradition, he is considered to have prepared the way for Jesus. He also baptized him in the Holy Spirit.
When considering The Search for Spock, the allusion to John the Baptist is important for two reasons. First, just as John is considered to have prepared the way for Jesus, this film is preparing us for Spock's resurrection through this subtle shout-out. Second, John was an apocalyptic preacher. He believed that "God is going to descend in some sort of a catastrophic event to solve the world" (Source).
In a very John-esque way of looking at the story, Spock can't be resurrected or normally returned to the Star Trek universe until some downright apocalyptic events play out.
Genesis, your days are number.
They Know Not What they Logic
The Biblical references don't stop there. The Search for Spock is just getting warmed up.
When David and Saavik come across Spock's burial tube, David opens it and finds it empty. Only Spock's burial robes remain. Let's set aside the huge plot hole of how a baby somehow opened the tube, crawled away, and did not instantly die, and let's focus instead on how this scene parallels the empty tomb of Christ.
When Mary Magdalene saw the stone to Jesus' tomb had moved, Peter and the other disciples investigated. Inside, they found only stripes of linen and the cloth that had been wrapped around Jesus' head. (Check out John: 20)
Then there's Spock's fashion choice at the film's conclusion. After his resurrection, Vulcan priests escort Spock from the temple, and he is clad in robes of pure white. Likewise, the Bible definitely mentions Jesus' preferred fashion statement of pure white robes. (Source)
But we saved the best for last. As Anton Karl Kozlovic has pointed out, Spock's story between The Wrath of Khan and The Search for Spock is basically a retelling of the Jesus' death and resurrection.
He wrote:
This half-human, half-Vulcan Christ-figure (just like Jesus was both human and divine) voluntarily sacrificed himself (via a fatal overdose of radiation) to save the crew of the starship Enterprise (microcosmically Earth) from sure death (Adamic sin), just like Jesus who gave his life as a ransom for the crew of planet Earth (Matt. 20:28; Mark 10:45). (Source)
Basically, if the Wrath of Khan represents Good Friday, then The Search for Spock is a science fiction retelling of the first Easter Sunday.
The Way and the Truth and the Logic
Okay, so that's our case for why Spock is a Space Christ Figure in The Search for Spock. But the question we want to ask now is (drum roll) why?
Why go to the trouble to set up these parallels between Spock and Jesus? How does this symbol serve the film thematically?
The answer to those questions will depend on you as a reader…because they'll likely be based on your understanding of Jesus as a historical and religious figure as well as how deep you want to go with your analysis.
But we'll unpack that a bit more.
Speaking broadly, we'd say the Jesus story—from a religious perspective—is one of hope. Hope of forgiveness, hope of life after death, hope of spiritual and physical healing, and hope that no matter how bad the world gets justice will ultimately prevail and better times will come.
In The Search for Spock, Spock represents this for Kirk, too. At the film's beginning, Kirk compares Spock's death to an "open wound" and grieves that he has "left the noblest part of himself back there on that newborn planet."
Throughout the film, it becomes evident that Kirk's quest for Spock is also a quest for hope and wholeness. He seeks forgiveness for is inability to save Spock previously as evident from his accepting the quest from Sarek to begin with. He is also looking to heal the wounds left by Spock's death, both the metaphorical "open wound" mentioned above but also the psychological wounds McCoy's suffering.
And a hope that there is life after death so he might be reunited with his friend:
KIRK: I'm not even sure that I believe, but if there's even a chance that Spock has an eternal soul, then it's my responsibility.
It might be million to one odds, but Kirk's desire to bring Spock back is so great that he's willing to roll them bones. No, not you, McCoy!
At the film's conclusion, Kirk directly draws comparisons between his search for Spock to a religious quest:
SAREK: Only time will answer. Kirk, I thank you. What you've done is—
KIRK: What I have done, I had to do.
SAREK: But at what cost? Your ship, your son.
KIRK: If I hadn't tried, the cost would've been my soul.
A Christian's desire to seek Christ is to save his own soul, and Kirk likewise would have lost his own had he not searched for Spock. Having found him, Kirk has also found hope and becomes whole.