But in some important matters, which gave Paul difficulties getting his converts to believe in, such as:
a) future resurrections (1 Cor 15:12-22) (despite �the Lord's own words ...�!)
b) the kingdom of God is not for �flesh and blood� (1 Cor 15:50)
Paul's inability to bring about �teaching� of Jesus was probably due to Jesus and disciples (such as Peter) believing in no resurrections and in the Kingdom to come on earth.
See here for a).
then search on > 6.2 < for b).
And what about the Kingdom to come soon?
In Paul's letter,
it's a given and likely the main cause for the
conversion of the early Christians. Paul did not have to offer
�teaching� of Jesus to secure that notion. Furthermore, it was
not in the interest of Paul to say that Jesus preached that more than
twenty years earlier!
And, since I happen to think that Jesus' main message was "Blessed are you who are poor, for yours is the kingdom of God." (ref: Lk6:20 & Mt5:3) (see here then search on > 16.2 <), Paul could not preach that, for reasons I explained in my aforementioned webpage (and Paul knew Jesus was poor: see here). In a few words, middle class & wealthy people had become converted and were providing money to Paul & his helpers.
Instead Paul focused on the �high context� Christ crucified (& resurrected), invoking revelation from above, and developing all kind of theological implications with the help of the OT. Any �teaching� bits from an uneducated poor Jew to other poor rural Galileans would then be rather puny, obsolete and irrelevant relative to that new Pauline Christology (however a few of them surface in the Q source: see here).