Re-baptism

Re-baptism, sometimes called Anabaptism, refers to the unbiblical practice of having one person Baptised several times.

As "True Baptism"

Some Christian denominations have practiced re-baptism in belief that the first baptism a person received was false.

Donatism

The Donatists, a schismatic group within Early Christianity, believed that if a person had been baptised by a priest who later went on to apostatize, that baptism became invalid. They were condemned by the rest of the Early Church, who stated that Baptism only required the righteous mediation of the Holy Spirit, not the mediation of a priest.

Anabaptism

The Anabaptists, a radical protestant denomination which rejected infant baptism, believed that when a person joined their church, that person must be re-baptised as infant baptism did not count.

This belief is sometimes carried into Evangelical or Baptist theology.

As Ritual Baptism

Some non-Christian religions practice Baptism as a way to achieve purity.

Second Temple Jews

Some Second Temple Jews practiced ritual bathing as a way to wash away sins. They would enter a ritual bath after committing a non-kosher act such as touching a dead body or an unclean object.

Mandaeans

The Mandaeans, a Jewish neo-gnostic sect which claims to be descended from the followers of John the Baptist, practises ritual baptism.