Christian baptism is not a baptism into a denomination, group, etc., but a baptism into the Christian faith, as grounded upon the ontological Trinity. This speaks of the universality (catholicity) of the true Church of Christ, marked by its confession of the Trinity, and that baptism in any of the different denominations, groups, etc. that have this Trinitarian confession is a valid baptism, as it is a baptism into the Trinity. Hence, Anabaptism (rebaptism) is definitely error of an egregious sort, if not utterly sinful (as absurd as regrowing foreskin for recircumcision!).
Dr. Francis Nigel Lee explains: