The Hebrew and Greek terms for "sons of God" are essentially the same, but the Old Testament always uses the phrase in reference to angels, whereas the New Testament always references the twice-born saints of God.
Our text for this day emphasizes the precise reason that our Lord Jesus prayed: "I pray not that thou shouldest take them out of the world. . . . They are not of the world, even as I am not of the world" (John 17:15-16). We who share this marvelous relationship bear both the "love the Father hath bestowed upon us" and the unique rejection that "the world knoweth us not, because it knew him not" (1 John 3:1).
Jesus said, "I am the light of the world" (John 8:12), and we who are His disciples are "the light of the world" (Matthew 5:14. We, unlike the angels, are to remain in this unfair and distorted world as lights. Consider this! We are the light that the Lord Jesus left in this world to represent Him and His message after He returned to heaven (John 9:5).
That is why the Scriptures refer to us as saints (holy ones) and disciples (followers); even the pejorative "Christians" (Acts 11:26) identify us as representing the King! We must therefore shine with the truth (John 3:19) and shed the "light of the glorious gospel of Christ" (2 Corinthians 4:4), attempting to "lighteth every man that cometh into the world" (John 1:9).
Finally, we are surely commanded to "walk in the light, as he is in the light" (1 John 1:7). Our light should never be covered in a "bushel" (Matthew 5:15), but set on a "hill" for all to see (Matthew 5:14). HMM III http://www.icr.org/article/6180/