The distinguishing mark of authentic believers is that their lives reflect godly character. This passage illustrates the seriousness of sin, and how to tell the difference between Children of God and Children of the devil. The way of determining each is through their nature. A child of the devil can only produce a nature that is in opposition to God. But, a child of God, by the seed implanted in them, can produce the fruit of righteousness. Sin will always be present but it will not be a way of life.