For years, "Dr. K" has taught that every Christian is responsible for evangelism. One of the passages of Scripture upon which he predicates his idea is John 7:37-39. He ties together this text with Jesus' teaching that he is the "water" of life (John 4:10). The logic is this: if Jesus is the water of life and rivers of living water are to flow from our innermost being after we become Christians, ergo, Christians are to be conduits of the drink of eternal life to others.
I have always found this interpretation of Jesus' words in John 7, a stretch. But then to my amazement I found this quote by the eminent theologian J. I. Packer.
Jesus, as recorded in John’s Gospel, had already declared what this new ministry would involve. It would not be the world’s first acquaintance with the Spirit of God, who had already (so the Old Testament tells us) been active in creation, providence, revelation, gifting for leadership, and renewing of hearts. But this would be the opening of a new era, all the same, with the Spirit adding a new role to the work he was doing already. Jesus would send the Spirit as “another Paraclete” (Helper, Supporter, Counselor, Comforter, Encourager, Advocate—paravklhto" [parakletos] has a wider range of meaning than any one English word can cover), to be not just “with” but “in” his disciples for ever (14:16–17). Through his coming Jesus himself, now absent in body, and his Father with him, would come and reveal themselves to disciples in a personal and permanent way, in a communion of love (14:18–23). As teacher, the Spirit would enable the apostles to recall and grasp what they had heard from Jesus, and would add more to it (14:26; 15:26; 16:13). Thus the apostles would come to see the full truth about Jesus’ glory (16:14) and so be qualified to bear faithful witness to him (15:27). Then through that witness the Spirit would convince people everywhere of the Christian facts (16:8–11; 17:20) and bring them through new birth to the living faith in Christ that marks entry here and now into God’s kingdom (3:1–15). Hereby the Spirit would engender in life after life the joy and influence that Jesus pictured as “living water” in flow out of the believer as a temple of God (7:37-39, cf. 4:10–14; Ezek 47:1–5).Note the last thought that the new life in Christ is one in which "living water" will flow from us. This living water is, according to Packer, centered on the "joy and influence" one will have for Christ. Joy is certainly not debatable. It is the idea of our "influence" for Christ that many believers still struggle with.
Packer's inclusion of our "influence" for Christ as a manifestation of the resurrected life is compelling and deserves our full attention.
Packer's point is that once Jesus calls us to himself we are made vessels for his service. It is through us that the Holy Spirit now calls others to himself. This is part of our great influence in the world for Jesus. Our joy is Christ. But our joy is also tied to our influence: that we are commissioned by Him to go into all the world and allow the water of life to flow through us to others in the saving message of redemption.