Luke stressed the joy that the Seventy experienced because they participated in God's program. As we have noted before, Luke often referred to the joy that Jesus brought to people (cf. 1:14, 46; 24:52; et al.). In view of Jesus' preparatory instructions (vv. 1-16) we might have expected the Seventy to feel miserable and glad the experience was over. However that is not normally the result of serving Jesus regardless of the hardships involved. As in the preceding pericope, Luke focused on Jesus' words to the messengers.
10:17 These disciples undoubtedly experienced the same opposition and rejection that Jesus did, but their overwhelming sentiment was joy (Gr. charas). They had experienced supernatural enablement and power because they trusted and obeyed the Lord (cf. 9:1; Matt. 10:8). They quite naturally rejoiced especially in the spectacular display of God's power evident in their control of demons. Jesus exorcized demons with a command, but His disciples had to command demons in Jesus' name, namely on the basis of His authority.
10:18 Jesus described the humiliation of Satan's demons as though it was a repetition of Satan's actual fall from heaven that happened before creation. Isaiah's description of the king of Babylon's fall was similar (Isa. 14:12). Many Bible students believe that Isaiah was describing the fall of Satan. Jesus may have been alluding to this passage. However, He appears to have been describing a current fall or humiliation symbolized by the subjection of the demons to His authority. This is more probable than that He described a vision that He had. Satan will experience similar humiliations in the future during the Tribulation (Rev. 12:7-10, 13), at the end of the Tribulation (Rev. 20:2), and at the end of the Millennium (Rev. 20:10). Jesus' victory over Satan gave Him as well as His disciples cause for rejoicing.
10:19 The power that Jesus had given the Seventy to escape injury symbolized their ability to overcome Satan and His demons spiritually (cf. Rev. 12:13-17). Thus the connection with the previous verse is clear. Jesus probably referred to snakes and scorpions because they represented these spiritual foes (cf. Gen. 3:15). This was evidently a special physical protection that Jesus gave His disciples during this mission. Jesus again gave it to His disciples following His resurrection (cf. Mark 16:18). However, that protection apparently lasted only a short time (cf. Acts 28:1-6). Jesus' disciples since then have experienced injury so it was evidently a limited provision in view of the unique ministry of Jesus' original disciples and apostles. Even during the apostolic age many disciples did not escape injury or death (Acts 7:60; 12:2; 2 Tim. 4:20).
10:20 As great as victory over injury and especially demons was, a greater cause for rejoicing was the Seventy's assurance that God would reward them. God makes note of those who commit themselves to participating in His mission. Jesus' comparison helps all disciples keep His blessings in their proper perspective.
There appear to be several records that God keeps in heaven. There is the book of the living, namely those who are presently alive on the earth (Exod. 32:32-33; Deut. 29:20; Ps. 69:28; Isa. 4:3). There is also a book containing the names of the lost and their deeds (Rev. 20:12). There is a book with the names of the elect in it (Dan. 12:1; Rev. 13:8; 17:8; 20:15; 21:27). A fourth book evidently contains the names of faithful followers of the Lord (Mal. 3:16; Phil. 4:3; Heb. 12:23; Rev. 3:5). In view of the context it was apparently to this last record that Jesus referred here.
This whole pericope deals with the joy that disciples who participate in God's mission for them experience. The greatest and most fundamental reason for rejoicing for any disciple is his or her personal salvation. Yet there is also joy for disciples who take part in God's program and advance His will in the world. It involves seeing a preview of the final victory over the forces of evil (cf. Matt. 16:18). This joy more than compensates for the deprivations and rejection that discipleship entails. Non-participating disciples know nothing of this joy.