The church of Jesus, near and far, at home and abroad, is on a global mission against the gates of hell.

Under God, and by the power of our all-authoritative Christ (Matthew 28:18), we raid the “domain of darkness” and carry captives to safety (Colossians 1:13). We go to spiritual sleepwalkers and say, “Awake, O sleeper, and arise from the dead, and Christ will shine on you” (Ephesians 5:14). We break into the house of the strong man, still bound by the Stronger One, and “plunder his goods” (Mark 3:27).

You might imagine, given such a mission, that God would arm his church with some spectacular weapons. But surprisingly enough, we join Jesus in destroying the devil’s works not mainly by casting out demons, or working miracles, or engaging in power encounters, but by teaching the truth.

Go . . . and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. (Matthew 28:19–20)

Missions as a Teaching War

Teaching may seem like a weak weapon to wield against the devil. Do knights slay dragons by persuasion? But in God’s hands, faithful teaching undoes one of the devil’s favorite schemes, as old as Eden and as subtle as that ancient snake: false teaching.

As Andy Naselli observes in The Serpent and the Serpent Slayer, the devil acts sometimes with obvious, spectacular opposition, and other times with hidden, unspectacular craft. Or, he acts sometimes like a dragon, and sometimes like a serpent (Revelation 12:9). As dragon, he devours; as serpent, he deceives. As dragon, he persecutes and oppresses; as serpent, he seduces and ensnares. As dragon, he breathes fire; as serpent, he whispers falsehood.

And between the two, the serpent may be the deadlier. In Eden, Satan could have terrified Eve with his fangs; instead, he lured and lied with his tongue — with his teaching (Genesis 3:4–5). And so he still does (John 8:44). False teaching felled the world, and false teaching keeps it in oppression.

“At every stage of the kingdom’s advance, the lie of the garden dies by the truth of the gospel.”

So, at every stage of the kingdom’s advance — from Jesus to his apostles to the church — the lie of the garden dies by the truth of the gospel. Teaching wins back the world.

Teaching Launches the Kingdom

Jesus did more than teach during his ministry — he healed, worked wonders, and cast out legions of demons. He attacked the devil’s domain with both the right hand and the left. But teaching was the central assault.

Following his baptism and wilderness temptations, his public ministry began when he “came into Galilee, proclaiming the gospel of God” (Mark 1:15). Indeed, the Spirit anointed him “to proclaim good news to the poor” (Luke 4:18), a mission that ever rested on the front of his mind: “I must preach the good news of the kingdom of God . . . for I was sent for this purpose” (Luke 4:43). Preaching and teaching were “his custom” (Mark 10:1), what he did “throughout all the cities and villages” (Matthew 9:35). “You call me Teacher,” he told his disciples, “and you are right, for so I am” (John 13:13).

The healings, the wonders, the spiritual authority — these were all fingers pointing to his kingdom-heralding, gospel-giving words. In fact, without embracing his teaching, the souls of former demoniacs were merely emptied and swept, inviting worse darkness to enter (Matthew 12:45). Only “the truth will set you free” (John 8:31–32), Jesus told some would-be disciples. And so, he taught.

Teaching Spreads the Kingdom

The apostles were not confused about what it meant to carry on their risen Teacher’s mission. The book of Acts records many demons cast out, wonders worked, and diseases healed, but the emphasis again lands on teaching — or, in Luke’s broad vocabulary, proclaiming (Acts 4:2), preaching (Acts 8:4), disputing (Acts 9:29), speaking (Acts 16:13), reasoning (Acts 17:2), proving (Acts 17:3), persuading (Acts 18:4), explaining (Acts 18:26).

The apostles, like Jesus, demonstrated the kingdom in both word and deed, but they were clear that the deeds served the words (Acts 3:11–16). Ultimately, it was the apostles’ Spirit-empowered teaching that turned hearts, toppled idols, saved sinners, and founded churches. And so, it was to the devil’s shame, but the apostles’ glory, to hear the Jerusalem council complain, “You have filled Jerusalem with your teaching” (Acts 5:28).

And more than Jerusalem. By book’s end, the teaching had broken out of Judea, run through Samaria, and begun to reach “the end of the earth” (Acts 1:8), liberating captives all along the way. The last verse pictures Paul in Rome — doing what? “Teaching about the Lord Jesus Christ” (Acts 28:31).

Teaching Grows and Guards the Kingdom

As the age of the apostles ended, the mission against spiritual darkness did not. And unsurprisingly, the apostle Paul placed teaching at the center of the church’s ongoing advance. Not only did he charge Timothy, his spiritual son, to devote himself to teaching (1 Timothy 4:11, 13; 6:2; 2 Timothy 4:2), but he labored to create a legacy of teachers: “What you have heard from me in the presence of many witnesses entrust to faithful men, who will be able to teach others also” (2 Timothy 2:2). Whatever happens, Timothy, make sure the church keeps teaching.

“Through teaching, God will grow and guard his kingdom in lands once ruled by lies.”

By teaching the truth, the elders of the church — and, under them, every member (Colossians 3:16) — proclaim the gospel and gather new believers; they also protect the gospel and guard believers from the ever-present threat of serpentine deception, including what Paul calls “teachings of demons” (1 Timothy 4:1). Such teachings are sometimes permissive, scratching ears and suiting passions (2 Timothy 4:3), and sometimes restrictive, banning marriage and forbidding foods (1 Timothy 4:3), but they are always false and always deadly.

And so, the church teaches and teaches and teaches — trusting that through teaching, God will grow and guard his kingdom in lands once ruled by lies.

God Empowers the Teaching

On the surface, Christian teaching may look unremarkable — as unremarkable as Jesus telling parables beside the sea, or Paul reasoning with some Thessalonian Jews, or Timothy unrolling the scroll to preach again. But through the ordinary words and phrases of faithful Christian teaching, God works wonders.

When the risen Lord Jesus told Paul to go teach, he also told him the effect his teaching would have:

I am sending you to open their eyes, so that they may turn from darkness to light and from the power of Satan to God, that they may receive forgiveness of sins and a place among those who are sanctified by faith in me. (Acts 26:17–18)

Through teaching, God works miracles greater than the multiplication of loaves, or the deliverance of demoniacs, or even the raising of Lazarus. He shatters our delusive darkness. He forgives our innumerable sins. And he frees his people from the power of Satan, that serpent of false teaching and forked tongue, and wins us back to himself.

So, in the church’s global mission against the gate of hell, words are our greatest weapons.