"My message and my preaching were not with wise and persuasive words, but with a demonstration of the Spirit's power, so that your faith might not rest on men's wisdom, but on God's power" (1 Corinthians 2:3-5).
In the work world, we are trained to press through obstacles, no matter the cost. However, perseverance that is not directed by the Holy Spirit is only sweat and toil. We must learn to walk the fine line between these two concepts. On this subject of relying on our human strength, Watchman Nee wrote:
I believe many people are so rich and strong that they give no ground for God to work. I frequently recall the words, "helpless and hopeless." I must tell God, "all that I have is yours, I myself have nothing. Apart from you I am truly helpless and hopeless." We need to have such a dependent attitude toward God that it is as if we cannot inhale or exhale without Him. In this way we shall see that our power as well as our holiness all comes from Him. Oh how God delights in seeing us coming hopeless and helpless to Him. A brother once asked me, "What is the condition for the working of the Spirit?" To which I replied that . . . the Holy Spirit must first bring us to a place where we can do nothing by ourselves.
Of course, God gives us our natural skills and He will use them, although it can be hard at times to tell whether it is God working through us or if it is our natural skill alone making things happen. We need to try to distinguish the difference even as we resist over-analyzing (which can result in paralysis by analysis).
The apostle Paul understood that it was not his ability to deliver eloquent sermons that changed people. It was the power of God working through him. If God's power comes through our work, that brings glory to the Father.