Jesus will redirect some of their excitement, but before turning to that, let me make a brief comment on the seventy or seventy-two. A majority of scholars believe that the number here should be seventy-two; some other manuscripts read seventy. It’s not surprising that early scribes who were copying the number considered both numbers significant. Jesus had already sent the twelve to expel demons and heal the sick (9:1). He no doubt chosen the number twelve to reflect his plan for the twelve tribes of Israel (Luke 22:30). Seventy, however, was the common Jewish reckoning of the number of gentile nations, based on the list of nations in Genesis 10. So this mission may prefigure the mission in Acts. Moses also appointed seventy elders over Israel (Num 11:16) in addition to heads of twelve tribes, and God empowered them to prophesy (11:25). But two other elders were not present, and God empowered them to prophesy also (11:26), bringing the number to seventy-two. In any case, Jesus is spreading the mission further, as Moses also would have liked (11:29).

Jesus sent them out to heal the sick and tell them while doing so, “God’s promised reign has come to you!” (Luke 10:9). That is, they were to preach that the expected kingdom of God was at hand, and people had to respond by either embracing this news or rejecting it. Jesus’s agents are heralds of God’s kingdom: “How beautiful upon the mountains are the feet of the messenger who announces peace, who brings good news, who announces salvation, who says to Zion, “Your God reigns” (Isa 52:7, NRSV; cf. http://www.craigkeener.org/good-news-about-jesus-christ-and-the-introduction-to-marks-gospel-mark-11/). As elsewhere in Jesus’s ministry, healing and deliverance demonstrated that the promised time had come (Luke 7:20-23; 11:20).

Now Jesus’s 36 pairs of disciples return with great news, reporting that not only were the “normally” sick healed, but that even demons had been subjected to them in Jesus’s name (10:17). They were subject “in Jesus’s name” because Jesus’s agents, who acted and spoke faithfully on his behalf, represented him—whoever accepted or rejected them, ultimately accepted or rejected him (10:16).

Jesus replies, “I was watching Satan fall from heaven like lightning!” (10:18). Is he changing the subject, only to return to it in the next verse (10:19)? We can take Jesus’s “watching” in one of two ways. One possibility is that Jesus refers to an earlier fall of Satan, noted in Jewish tradition (and probably reapplied in another way in Rev 12:9—but that is another story). (Contrary to popular thought, it is not reflected in Isaiah 14, or at least not directly; the context there refers only to the arrogant, self-deifying king of Babylon; see http://www.craigkeener.org/does-isaiah-1412-14-refer-to-lucifers-fall-from-heaven/.)

Thus he would be saying, “You don’t need to worry about Satan. He lost his place before God a long time ago!”

This makes sense, but the other possibility might make even better sense. Jesus could be saying, “As you were preaching God’s reign, I was watching Satan fall, being displaced from his authority in heavenly places. God’s kingdom was taking back ground that the devil had usurped.” In other words, Jesus was watching Satan’s kingdom retreat during his disciples’ mission. Jesus does in fact view his ministry of deliverance as an assault on Satan’s kingdom (Luke 11:18); he is liberating the strong oppressor’s possessions (11:22; 13:16; cf. Acts 10:38). Paul, too, understood his mission of proclaiming God’s kingdom as delivering people from Satan’s authority to serve God instead (Acts 26:18). Satan does claim authority over earthly kingdoms (Luke 4:6), though only under God’s permission and ultimately God can overrule him (Dan 4:32).

But how would this second possibility fit Satan falling “from heaven”? If we use NT cosmological imagery, Satan works on earth from a position above it (see e.g., Eph 2:2; 6:12). More importantly, even the immediate context applies this language figuratively for one who is exalted being cast down. Because Capernaum, privy to much revelation of Jesus’s identity, did not respond even more radically to his identity, Jesus declares, “And you, Capernaum: you won’t be lifted up to heaven, will you? No! You’ll be thrust down to the underworld!” (Luke 10:15). Scripture often uses such language figuratively; compare Lam 2:1: “He has cast from heaven to earth the glory of Israel” (NASB). It would seem even more appropriate for Satan, already fallen and now being displaced from authority through the advance of Jesus’s kingdom forces in Luke 10:17.

Indeed, Jesus was granting them authority over Satan’s ground forces: “I have given you authority to trample on snakes and scorpions and to overcome all the power of the enemy; nothing will harm you” (10:19, NIV). Here Jesus echoes the idea in Ps 91:13: “You will subdue a lion and a snake;you will trample underfoot a young lion and a serpent” (NET). (This is the same psalm the devil earlier tried to manipulate Jesus into abusing in Luke 4:10-11; Jesus, by contrast, does have authority to apply it the right way.) We see an example of this authority in a more literal sense in Acts 28:3-5, where Paul is unharmed by a viper. Traveling dirt footpaths throughout Galilee to proclaim him, Jesus’s agents would indeed value protection against snakes. But in this context, Jesus undoubtedly also implies protection against spiritual serpents such as the devil (cf. 2 Cor 11:3, 14; Rev 12:9; 20:2).

Jesus thus acknowledges their observation: indeed, demons are subject to them (Luke 10:17-19). But then he qualifies their celebration with another observation. There is far greater cause for celebration than the subjection of demons. They can rejoice that their names are written in heaven (10:20); salvation is the greatest reason to celebrate (15:7, 10, 32; Acts 13:48; 15:3), and rewards in heaven are causes for joy (Luke 6:23). Satan has been cast down from heaven (Luke 10:18), but they are established in heaven! This draws on the earlier biblical image of God’s record book (Exod 32:32; Ps 56:8; 69:28; 139:16; Mal 3:16), elaborated in Jewish tradition and noted elsewhere in the NT as a heavenly book of life (see esp. Phil 4:3; Rev 3:5; 13:8; 17:8; 20:12, 15; 21:27).

We celebrate many divine gifts, but the greatest of all is knowing that we can spend forever in the Lord’s presence, fulfilling the purpose for which we were designed. We may rejoice at exegetical insights, at opportunities to preach and see others turn to God, and even at discovering that as Jesus’s agents we can expel hostile spirits. But the ultimate cause of celebration is eternal life. It belongs to all who have come over to God’s side, who have embraced his kingdom, through Jesus. If you should happen to be reading this and not know whether you have that assurance, you have only to ask God for it in Jesus’s name. The God who gave his own Son to bring you to himself will certainly welcome you if you come.