Philippians 2:12,13 Wherefore, my beloved, as ye have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling. For it is God which worketh in you both to will and to do of his good pleasure.
The phrase "work out your own salvation" has been misunderstood and misapplied for 2,000 years. It doesn't mean to work to be saved or to stay saved. (Eph. 2:8-9). These people in the Philippian Church were already saved.
Fear and trembling reminds us just how prone we are to fail. To fear the Lord with trembling is to reverence the Holy Lord. As we reverently study the Bible, we will grow deeper in the things of God, ever growing toward maturity.
The Christian life is not one of defeat and misery. It's a life of progress, joy and victory.