There is no such thing as an accidental overcomer. Faith is not some static theological concept, it must take action, actions that are consistent with God's character and Word. The Bible teaches us that overcomers are fearless in delivering, driven by a faith that overcomes all obstacles this world and Satan can throw at us. Fear will keep us from victory. Fear is a lack of faith.
Fear distorts our picture of what is real.
Fear does not let us see God as we should. Too many Christians live their lives in fear rather than faith. Fear makes us unproductive and paralyzed as Christians and keeps us from glorious victories for God. David drew up his faith based on a long standing record of God's glorious faithfulness throughout the past in other great heroes of faith. Because that's the way they built them in England, and American railroads were built by British expatriates.