Paul was accepted by the Apostles, including Peter, the rock on which the Church was built, and John, the disciple whom Christ loved. From a Christian point of view that makes Paul's conversion and contact with Christ basically unimpeachable.
It is certainly true that Christ trumps Paul, and, except for a few Protestants down the ages, the Gospels have always been treated with greater reverence than the epistles. But I'm always perplexed when people say things like Christ was more tolerant than Paul. Actually, Christ often is clearly marking out the path of perfection, the path of the Saint. Hence, we see Christ say things like to look on a woman with lust is to commit adultery in your heart. Paul actually adapts Christianity, providentially no doubt, to the Gentiles and with far greater emphasis on the spiritual path of the average, sinful man. There are imbalances in Paul's perspective no doubt, which will burst forth in Augustinian and then, even more so, in Protestant Christianity (Luther's devotion to a Pauline position is so strong as to make him refer to the epistle of James as the epistle of straw and wish to remove it from the Scriptures, for example).