Mark 9:40 Commentary: Not Against Us Is for Us

This verse sits within a larger section of Mark where Jesus repeatedly challenges his disciples’ assumptions about greatness and exclusion. In verses 33, 35, he catches them arguing about who is greatest; he answers by placing a child in their midst and redefining greatness as service. Then in verse 38, John reports a man casting out demons in Jesus’ name but not following the disciples, the implication is that the disciples told him to stop. John says 'we forbade him, because he doesn’t follow us.' That phrase matters: the disciples’ concern is not that the man is opposed to Jesus, but that he does not belong to their group.

Jesus’ response in verse 39, 'Don’t forbid him', begins with a reason: no one who does a miracle in his name will quickly speak evil of him. Then verse 40 generalizes: 'For whoever is not against us is for us.' The logic is that a person actively using Jesus’ name to do good cannot be an enemy; their work testifies to some level of allegiance.

The incident echoes Numbers 11:26, 29, where Joshua urges Moses to forbid Eldad and Medad from prophesying because they had not come to the tent of meeting. Moses replies, 'Would that all the Lord’s people were prophets.' Clarke sees the same 'bigoted spirit' in Joshua and John, and the same 'candour and benevolence' in Moses and Jesus. The cultural context of first-century Judaism included competing groups (Pharisees, Essenes, various prophetic movements), exclusivism was common. Jesus deliberately counters that instinct. The house in Capernaum (v. 33) where this teaching occurs is likely Peter’s home, making the setting intimate: a private rebuke meant to reshape how these leaders view others who serve the same Lord.

Clarke notes a significant textual variant: instead of 'us' (ἡμῶν) in verse 40, many manuscripts read 'you' (ὑμῶν), including Syriac, Coptic, Ethiopic, Gothic, Slavonic, Vulgate, and Itala. He argues that 'you' fits the context better: the man did not follow 'us' (the disciples) but was not against 'you' (Jesus). However, modern critical editions of the Greek New Testament (NA28, UBS5) read 'us' (ἡμῶν) on the strength of earlier Alexandrian manuscripts. The external evidence is divided, but the internal logic of the passage, where Jesus repeatedly addresses the disciples’ possessive attitude, supports either reading without changing the essential lesson. No other significant variants affect this verse.

Throughout church history, Mark 9:40 has been a key text for resisting narrow sectarianism. Early church writers, such as Cyprian of Carthage, cited it to argue that those who suffered for Christ but were not in full communion with the bishop could still be counted as martyrs. During the Reformation, Calvin used the verse to argue against overly strict church discipline that would silence legitimate preaching by non-ordained persons, though he cautioned against giving 'loose rein to rash men.' In the 18th century, Wesley and Clarke drew on the verse to promote interdenominational cooperation in evangelism. Modern ecumenical movements often appeal to it as a biblical warrant for recognizing Christian work across denominational lines. At the same time, conservative traditions have used the parallel in Matthew 12:30 to maintain that the principle does not license doctrinal indifference, the verse has thus served both as a call to charity and a checkpoint for discernment.

Three-point outline

1. The disciples’ mistake: confusing group loyalty with kingdom loyalty. John assumes that because the exorcist is not part of the apostolic band, he should not operate. Jesus disagrees. The issue is not authority but fruit, the man is casting out demons in Jesus’ name, and that is the only credential needed.
2. Jesus’ principle: assess by direction, not affiliation. Verse 40 does not say everyone is on our side; it says those who are not against us should be treated as for us. This is a generous default, not blind trust, but a presumption that good work in Jesus’ name deserves room.
3. The limit of the principle: it applies to action, not idle neutrality. In Matthew 12:30, where religious leaders actively oppose Jesus, the standard is different. Here, the man is doing positive good. The two sayings together call for discernment: who is a real opponent, and who is simply not in our circle?

Five-point outline

1. Jesus corrects an exclusive spirit among his own disciples. The rebuke is gentle but firm: 'Don’t forbid him.'
2. He provides a test: works done in his name are evidence of allegiance. A person cannot invoke Christ’s power and then quickly turn and curse him.
3. He sets a default: presume good will unless proven otherwise. 'Whoever is not against us is for us', this becomes the operating assumption.
4. He immediately follows with a promise of reward for even small acts. Verse 41 extends generosity: a cup of water given in his name will be rewarded. The same principle applies.
5. He then warns against causing believers to stumble. Verse 42 shows that the inclusive principle does not mean moral laxity, those who harm the vulnerable face severe judgment.

Illustration hooks

• The church volunteer who attends a different congregation. She leads the food bank but hasn’t joined your membership; some question whether she should serve. Jesus’ words ask us to look at the fruit instead.
• The coworker who prays with you but holds different theology. He invokes Jesus’ name sincerely, even if you disagree on secondary doctrines. The challenge: can you celebrate his faith without fixing him first?
• The joint community project where churches work together. Pastors from various traditions cooperate for a city outreach. Someone grumbles, 'They’re not really our kind.' Jesus says their work is enough.

Questions your congregation is asking

• Does this mean everyone who says 'Lord, Lord' is really saved? (Jesus elsewhere warns of false prophets, but the principle here is about recognizing allies, not final judgment.)
• What about people who claim to do miracles in Jesus’ name but teach error? (The same Jesus who says 'not against us' also calls false teachers wolves, discernment remains needed.)
• How do I know when someone is 'for us' if they don’t join our church? (Look for three things: they use Jesus’ name, they oppose the enemy, they serve others. That’s enough to treat them as friend.)

This passage challenges our instinct to control who can do God’s work. John and the disciples thought they were protecting Jesus’ reputation; Jesus tells them they are obstructing the kingdom. As you read Mark 9:38, 41 together, ask yourselves: where are we too quick to say 'no' to people serving Jesus in ways we don’t recognize?

Discussion questions

1. Why did John and the other disciples forbid the exorcist? What does that reveal about their mindset at this point in the story?
2. Jesus gives a reason in verse 39: 'no one who will do a mighty work in my name and be able quickly to speak evil of me.' What logic is he using here about the link between action and allegiance?
3. How do you reconcile verse 40 ('whoever is not against us is for us') with Matthew 12:30 ('he who is not with me is against me')? What difference in context explains the two statements?
4. In what situations today might we be tempted to forbid someone who is doing good in Jesus’ name but does not belong to our church or tradition?
5. Verse 41 says even a cup of water given 'because you are Christ’s' will be rewarded. What does that tell us about how God values everyday acts of kindness done in his name?
6. How can a small group cultivate a 'generous default' toward other believers without falling into indifference about truth?
7. Share about a time you were surprised to find an ally in a person or group you initially distrusted. What changed your view?