Probably in our own, modern substitutes for (immediate baptism upon profession) – raising hands, coming forward, etc. – are the result of a felt need to do something for those who believe. It seems certain that those who believed were distinguished from those who did not. There is no evidence that the New Testament evangelistic preachers asked them to come forward, but there is every indication that they did invite those who believed to be baptized (Ac. 2:38). And it seems that this was the way in which new converts professed their faith in Christ and came under the care and discipline of the church.
Jay Adams