I am often asked about the relationship between good works and the grace of God. The Bible is clear that the grace whereby we are delivered from the the domain of darkness and transferred into the kingdom of God the Son, and progressively sanctified is wholly unmerited, unearned, and unearnable. Yet, the Word of God is equally clear that we are to work out our salvation, to run the race with vigor, and to be zealous for good works.
Paul seems always to rise to the occasion when answers are needed, and this case is no exception. Colossians 1:26-29 provides the paradigm for understanding the relationship between God's work, and ours. Paul gives his personal mission statement here, declaring that Christ "in us" is the hope of glory, and the reason the message of Christ can bring all who believe to spiritual maturity. And then he gives us this: "For this I toil, struggling with all his energy that he powerfully works within me." Hear what Paul is saying: "I work hard. I toil. I struggle, but always with the energy God is powerfully working in me."
We could put it this way: "How do I now when the power of God is at work in me?" Answer: "When I am laboring and toiling to turn from sin and temptation, and struggling mightily to be obedient in all things." God's power in me is demonstrated in my labor for him.