I Thessalonians 5:5
Ye are all the children of light, and the children of the day: we are not of the night, nor of darkness.
We are literally sons of light and sons of day. In Scripture, the believer’s condition is consistently associated with light in the New Testament. This phrase comes from a Hebrew idiom, and the blessed meaning is this, that as sons resemble their fathers, so believers are in character, light, intellectually and morally illuminated to be able to resemble their heavenly Father.