Note 13 at 1Co 1:29: The primary reason that God chooses to use those who are nothing by the world's standards is so that no one else will take the credit for the great things that are accomplished.

If the Lord used those who had it "all together" in the natural, then people would share the glory that rightfully belongs to God alone. However, when the Lord works miraculously through those who have no obvious talent or ability, everyone says, "This must be God" (see note 10 at 1Co 1:26).

This not only keeps others from misdirecting the glory that belongs to God, but it also keeps the person whom God uses from being swelled up with pride. One of Satan's greatest weapons against those who are being used by God is the temptation to think that the Lord is using them because of some superior virtue that they possess.

Keeping these scriptures in mind will help deflate that ego. God uses nobodies. If we think we've become somebodies (in our flesh), we will cease to be used. He will not share His glory with anyone else (Isa 42:8).