I don't consider Paul's words in 1 Cor. 12:13 to be doctrine of men:
"For by one Spirit we were all baptized into one body, whether Jews or Greeks, whether slaves or free, and we were all made to drink of one Spirit."
Paul was speaking to the Corinthian believers ... and he says they were ALL baptized into one body ... that can only be true if spirit baptism happens at conversion.
So the Scripture, I cited, that specifically says otherwise is to be ignored? Jesus parable of the Scattering of the Seed is to be ignored?