A shared foundation for the church
Paul wrote Ephesians 4 as an appeal for believers to live humbly and keep the unity God had given them. He names one body, one Spirit, one hope, one Lord, one faith, one baptism, and one Father. These are not private preferences. They are the common foundation of Christian life (Ephesians 4:4-6).
So “one baptism” is not mainly a demand that every church use identical procedures. Paul’s central concern is unity in Christ. Baptism marks entry into the visible community of people who confess the same Lord, not a reason to form competing spiritual groups.
One Lord, one faith, one baptism,
Baptism is tied to Christ
In Romans, Paul connects baptism with Jesus’ death and resurrection. Those baptised into Christ are pictured as sharing in his death and burial, then being raised to live differently (Romans 6:3-4). The point is not that a person earns new life by performing a ritual. Christ’s saving work is the centre.
Baptism is a powerful sign because it directs attention to Jesus. It says, in a visible way, that the old life of sin is no longer the believer’s master and that their hope rests in the risen Christ. That shared connection to him is why baptism belongs in Paul’s list of Christian unity.
Therefore we are buried with him by baptism into death: that like as Christ was raised up from the dead by the glory of the Father, even so we also should walk in newness of life.
One body, with many backgrounds
The Corinthian church knew how easily people could divide over status, gifts, and personalities. Paul reminded them that the Spirit had brought Jewish and Gentile believers, enslaved and free people, into one body (1 Corinthians 12:13). Their histories had not vanished, but none of those differences decided their worth or place in Christ.
That helps explain the force of one baptism. No Christian has a superior baptism because of family, culture, eloquence, or the reputation of the person who baptised them. All who come to Christ come by grace, and all are called to receive fellow believers as members of the same family.
For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.
Why Christians still practise baptism differently
Faithful Christians have reached different conclusions about infant baptism and believer’s baptism, and about immersion, pouring, or sprinkling. Ephesians 4:5 does not settle each of those questions by itself. Some readers stress baptism as the response of a person who has trusted Christ, as those who received Peter’s message did in Jerusalem (Acts 2:41). Others see baptism also as a covenant sign given within believing households.
Even where Christians disagree, Paul’s words push against contempt. Baptism should lead people towards Christ and his people, not towards pride. If you are thinking about baptism, read Ephesians 4:1-6 and Romans 6:3-4 for yourself, then speak with mature Christians in a local church about how to take that step faithfully.