There are several places in the Bible where we see the Lord was giving Paul revelation. I'm far from an expert on Paul's journeys and his progressive revelations, but I see here where Paul was chosen and would be given such revelations in the future.
Acts 9:15-16 But the Lord said unto him, Go thy way: for he is a chosen vessel unto me, to bear my name before the Gentiles, and kings, and the children of Israel: 16 For I will shew him how great things he must suffer for my name's sake.
Clearly, Paul was a chosen vessel with a message that would be revealed by the Risen Lord, Himself. Do you deny what Paul writes here?
Eph. 3:1-9
3 For this cause I Paul, the prisoner of Jesus Christ for you Gentiles, 2 If ye have heard of the dispensation of the grace of God which is given me to you-ward: 3 How that by revelation he made known unto me the mystery; (as I wrote afore in few words, 4 Whereby, when ye read, ye may understand my knowledge in the mystery of Christ) 5 Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit; 6 That the Gentiles should be fellowheirs, and of the same body, and partakers of his promise in Christ by the gospel: 7 Whereof I was made a minister, according to the gift of the grace of God given unto me by the effectual working of his power. 8 Unto me, who am less than the least of all saints, is this grace given, that I should preach among the Gentiles the unsearchable riches of Christ; 9 And to make all men see what is the fellowship of the mystery, which from the beginning of the world hath been hid in God, who created all things by Jesus Christ: