Jesus gave his Apostles the authority to preach the Gospel and once it got started it could not be stopped because some little nobody out there some where will be preaching it.
All of them the same Gospel? All of them with the same authority? Gnostics - then and today - as well? Benny Hinn? Peter Popoff? Who is to say they do not have the same authority?
History and experience show this to be a impractical and unsuccessful way to transmit the true Gospel. Which is why Jesus established His Church and gave her authority.
What did St. Paul give as his authority?
Gal 1:6
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I marvel that ye are so soon removed from him that called you into the grace of Christ unto another gospel:
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Which is not another; but there be some that trouble you, and would pervert the gospel of Christ.
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But though we, or an angel from heaven, preach any other gospel unto you than that which we have preached unto you, let him be accursed.
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As we said before, so say I now again, If any man preach any other gospel unto you than that ye have received, let him be accursed.
Already there were men trying to pervert the Gospel of Jesus.
I have the words that Jesus spoke, so if some one tells me that i am not supposed to do unto others as i would have them do unto me, i will know that they are not being truthfull.
If some one tells me there has been no resurection all i need to do is show them by the scripture they are wrong.