1 Corinthians 2:2
 For I determined not to know anything among you except Jesus Christ and Him crucified.

Paul was, to say the least, a brilliant theologian. his knowledge of the Old Testament was surpassed by none and his intellectual understanding of The Lord has been challenged only by fools. He was ministered to by Christ Jesus Himself for three years in the Persian wilderness and lived his life as a sacrifice to The Lord. Take that in comparison with myself and if I had any inclination to boast in any amount of scriptural knowledge, that has been cast far away. If we as Christians are here as Jesus' hands and feet what business should we be about other than professing the Gospel which is the life, death, and resurrection of Jesus? That is what is going to save lives and create disciples. Not some earthly wisdom. It is the cross that has saved me and it should be the cross that I profess without shame.
Application: I would rather not witness than for my motives in doing so to be myself being exalted. It is all for His glory.