What does the doctrine of baptism teach?

The doctrine of baptism centers on the believer's union with Jesus Christ. As highlighted in Romans 6:3, believers are baptized into Christ's death, signifying that they share in His substitutionary atonement. This union means that what Christ achieved on behalf of sinners is credited to them. Therefore, baptism represents not only an act of obedience but an incorporation into the saving work of Christ. The teachings in Hebrews, especially regarding the plural 'doctrine of baptisms' (Hebrews 6:2), depict various baptisms—each emphasizing the believer's relationship with Christ and illustrating the whole gospel narrative of redemption.