Those who walk in the light of truth will emit light to those around them. They are living witnesses for Christ. They will not be like the world, living in moral darkness, loving themselves and the things of the world, and seeking for earthly treasures. They will be “a peculiar people, zealous of good works.”. RH October 31, 1878, par. 7
I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me.
John 17:23 (KJV)
The children of God are called to be representatives of Christ, showing forth the goodness and mercy of the Lord… SC 115.1
If we do represent Christ, we shall make His service appear attractive, as it really is. Christians who gather up gloom and sadness to their souls, and murmur and complain, are giving to others a false representation of God and the Christian life. They give the impression that God is not pleased to have His children happy, and in this they bear false witness against our heavenly Father. SC 116.1
And Joseph was brought down to Egypt; and Potiphar, an officer of Pharaoh, captain of the guard, an Egyptian, bought him of the hands of the Ishmeelites, which had brought him down thither. And the LORD was with Joseph, and he was a prosperous man; and he was in the house of his master the Egyptian. And his master saw that the LORD was with him, and that the LORD made all that he did to prosper in his hand.
Genesis 39:1-3 KJV
Unbeliever sees God in you, the prove God is working in you and make Him very attractive.