The text describes the Christian work-out. We become blameless, nothing wrong in us that has not been addressed according to the instruction of God. We become harmless or innocent by right motives for actions. We become identified as God's children. We become without rebuke, no just criticism can be leveled.
Christians shine as lights for understanding, guidance, warning and encouragement.
Christians hold forth the Word of life to bring the lost to Christ. He rejoices in the day of Christ. His works are rewarded.