Baptism is the gate, but what it accomplishes is disputed along the same line as everything else: sacramental traditions hold it effects regeneration, memorial traditions hold it publicly signifies a change already made. In practice, mutual recognition of baptism is Christianity's strongest thread — most churches accept a Trinitarian baptism performed anywhere — which is why converts between most denominations are received rather than re-baptized. The exceptions are exactly the credobaptist groups, and the disagreement is old enough to have gotten people killed.