Christ not having died and been raised from the dead, how could Elijah and Moses come before Him? As I understand, Christ was the first to go to heaven.
But it nowhere says that Christ was the first to go to heaven. It does say that He is "the first-fruits of them that slept," called that Because He is the preeminent One among those raised from the dead, and (2) He is the One virtually by whose merit all others are brought from the dead. Ephraim was called the first-born, not because he was that, for Manasseh was the first-born, but Ephraim had the preeminence. Israel is called the first-born altho literally Esau was, but Israel had the preeminence. So Christ is the preeminent One, "the First-born of the dead," "the first-fruits," because He is the preeminent One through whom all come back from the dead, through whom all is life. The expression in John 3:13 refers not simply to ascending to heaven, but ascending to heaven and coming back to give the message of God. Christ is the only One who has descended out of heaven to give God's message.