It was Rueben, who begged them not to and reasoned with them.  We must also remember that jealousy is as cruel as the grave, and that James:1:20: For the wrath of man worketh not the righteousness of God.  These will not minister grace or God-applied judgement to our steps. 

If we glory, we are to glory in the cross of Calvary.  This is the reason that we are called; to let people know of the wonderful salvation that is provided through the shed blood of Jesus Christ.  Not to inform them of how great we are, so much so, that Jesus could not help but want us on His team.

A good question to ask yourself is "why do you want to preach, or win souls or be used in spiritual gifts.  Be honest with yourself.  The desire for spiritual things is admonished in the word of God.  It shows our desire for the realm of God our Father. 

There is potential for sacrifice in our relationship with Jesus Christ if we truly have a deep desire for spiritual things. It will take sacrifice to have a truly profitable ministry. There is potential for failure if we desire only the carnal appearance of being great before men.