It might be a good idea to check with ourselves what the cross of Christ actually means in our life. Most of the time we are so used to it that we are at risk to empty the cross of its power.
If we rely on our own wisdom, our own insight, and our own thinking, then the cross is bound to be annoying; a stumbling block. After all, when we are so self-centered, then we think we do not need redemption! Surely, we can lead a rather Christian life, even study theology without having anything to do with the cross.
Paul had a keen mind, he was a Pharisee and as for righteousness based on the law, faultless. Yet, for the sake of Christ, he considered all this garbage (Philippians 3:8), and he resolved to know nothing while he was with the people of Corinth, except Jesus Christ and Him crucified (1 Corinthians 2:2). From a human standpoint that is foolishness. But we rob the cross of its power and we trample the fulfilled work of Christ, when we still think we can rely on our own possibilities.
Paul did not rely on his own knowledge. He came in weakness with great fear and trembling. He did not want to empty the cross of its power by clever preaching and an excellent choice of words. His only desire was to magnify God, to honor Him, and not to be impressive himself.
If we really long to serve God, then we should dare to be weak, then we should dare to remove from our life anything we rely on apart from the Lord. To Paul this was the great discovery of his life: if we are weak, our testimony has power, because only a word that comes from God, will be powerful.