I've been wanting to ask you about this but didn't want to bog down the discussion. Since the other point is at a stale mate, I'm curious what is your understanding about this.
When do you believe Paul got the details about the doctrine of grace especially concerning baptism?
Any answer as to the timing beyond, "Shortly after his conversion.", would be speculation.
What we know is that Paul's gospel was not given to him by man, nor was he taught it but that it was given to him by direct divine revelation (Gal. 1:12). We know that it was different than that understood and taught by the Twelve and that Paul was sent, again by divine revelation (Gal. 2:2), to Jerusalem specifically for the purpose of explaining his gospel to them which they then accepted as being from God and agreed with him that they should minister to Israel while he would go to everyone else (i.e. the Gentiles) (Gal. 2:6-9).
Now, even that much is something of an over simplification of things because Paul went first to the Jew and did not go exclusively to the Gentiles until Acts 13 and so there was clearly a process that God was bringing Paul through during the first years of his ministry. By the end of which, things like circumcision, baptisms, tongues, miracles, prophesies, etc, all of which have to do with the flesh, had faded away, crossing from the Law to Love. (I Cor. 13)
What do you think this passgae means? What baptism is it refering to?
Ephesians 4:4 There is one body and one Spirit, just as you were called in one hope of your calling; 5 one Lord, one faith, one baptism; 6 one God and Father of all, who is above all, and through all, and in you all.