Paul had a special calling as an apostle because ...
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And I fell unto the ground, and heard a voice saying unto me, Saul, Saul, why persecutest thou me? And I answered, Who art thou, Lord? And he said unto me, I am Jesus of Nazareth, whom thou persecutest. And they that were with me saw indeed the light, and were afraid; but they heard not the voice of him that spake to me. And I said, What shall I do, Lord? And the Lord said unto me, Arise, and go into Damascus; and there it shall be told thee of all things which are appointed for thee to do.
-Acts 22:7-10
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:
-Acts 9:15
Neither went I up to Jerusalem to them which were apostles before me; but I went into Arabia, and returned again unto Damascus.
-Galatians 1:17