"But the Lord said to him [Ananias], “Go, for he [Paul] is a chosen instrument of mine to carry my name before the Gentiles and kings and the children of Israel."
Apart from that, Peter also understood that Paul had been authenticated by Jesus as his apostle, see 2 Peter 3:
"Bear in mind that our Lord’s patience means salvation, just as our dear brother Paul also wrote you with the wisdom that God gave him. He writes the same way in all his letters, speaking in them of these matters. His letters contain some things that are hard to understand, which ignorant and unstable people distort, as they do the other Scriptures, to their own destruction."
Being an apostle meant that Paul was expressly authorized and enabled to represent the Lord. Hence the saying, "you can't slip a piece of paper..." meaning that one can't try and play one off against the other, as if they hold opposing views. Paul represents Jesus, nothing more, nothing less. Paul is merely a servant, the words are those of Jesus.
Then again, God told Mohammad that Jesus wasn't dead at all, so clearly Paul and therefore Ananias are unreliable. Which just goes to show that when you base your chain of reasoning on believing people claiming God spoke to them, you get into all kinds of contradictions. Because lots of people claim God have spoken to them, and He does not seem to be very consistent in his messages.
What does this even mean? Jesus never mentioned Paul, and Jesus and Paul never even met.