2 Corinthians 4:6-7 For God, who commanded the light to shine out of darkness, hath shined in our hearts, to give the light of the knowledge of the glory of God in the face of Jesus Christ. But we have this treasure in earthen vessels, that the excellency of the power may be of God, and not of us.
It is a purely amazing reality that God would choose to use the common believer to be a revelation of His glory. You have certainly seen and experienced this. This happens in the common and usual events of life as the holy and sanctifying influence of Christ, the Holy Spirit and the Scriptures is reflected in how God’s true followers live and respond to life. It is seen in their gentleness, their patience, their quietness and confidence. This reflection of the glory of God has a powerful influence that sits as the very root of what service for God means. That is the sense of what Paul stated earlier in this same portion of Scripture:
2 Corinthians 4:2 But have renounced the hidden things of dishonesty, not walking in craftiness, nor handling the word of God deceitfully; but by manifestation of the truth commending ourselves to every man's conscience in the sight of God.
All fruitful and productive Christian labor is rooted in this necessity. It is where the conscience of man is touched (we may say plowed and prepared for seed) and fruitfulness is made possible. God has chosen to make the holiness of His people the necessity of fruitfulness. Connect with this Romans 12:1:
Romans 12:1 I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.