1 John 1:6 If we say that we have fellowship with him and walk in the darkness, we lie, and do not the truth:
1 John 1:7 but if we walk in the light, as he is in the light, we have fellowship one with another, and the blood of Jesus his Son cleanseth us from all sin.
Darkness -Original Greek word
, transliterated word – skotos, Phonetic spellingskot'-os, meaning “night darkness” or “darkened eyesight or blindness”. Some time it means physical darkness (Matt 27: 45; Mk 15:33), it also means spiritual darkness, which implies ignorance or error (Jn 3:19; Rom 2; 19).The Greek word
comes from the base word 
, translated as “shade caused by the interception of light” or “an image cast by an object and representing the form of that object”.John exhorts his readers not merely to see that God is light, but also to “live in the light.” To this end he counters those who claim union with God while really living in darkness (v 6), and demonstrates the effect of “living in the light” (v 7).
This verse is followed by a series of criticism. John takes up three claims that people make, but which must be assessed in the light of their real character. It is probable that these were real statements made by people in the Church to which John was writing and that they reflect the outlook of the people who were causing trouble in the Church.
Most probably they were deceived in thinking that they could have fellowship with God while they practiced sin. They thought they had fellowship with God, but John calls them to realize that their experience was not really the fellowship of God. John was drawing their attention to certain characteristics of their way of life and branding these as sinful, and hence as signs of living in the darkness.
It is known that to walk, in scripture account, is to order and frame the course and actions of the moral life, that is, of the life so far as it is capable of subjection to the divine law. To walk in darkness is to live and act according to such ignorance, error, and erroneous practice, as are contrary to the fundamental teachings of our spiritual path. Now there may be those who may pretend to great attainments and enjoyments in religion; they may profess to have communion with God; and yet their lives may be irreligious, immoral, and impure.
Dr. John Gill commends in John Gill's Exposition of the Entire Bible, “…in the darkness of sin, ignorance, and unbelief, or are in a state of unregeneracy and blindness; whose understandings are darkened, and they know not God in Christ, nor have any true sight and sense of themselves, their sin and danger; and areignorant of Christ and his righteousness, and the way of salvation by him; and are strangers to the Spirit of God, and the work of his grace; and are unacquainted with the truths of the Gospel; and not only so, but go on in darkness more and more; prefer it to the light, love it, and the works of it; have fellowship with them, and choose them; take pleasure in the ways of sin and wickedness, and continue, and walk on in them; if such persons pretend to fellowship with God, they are liars…”
When we live in the darkness, we are alienated from God and the purposes of God. If we continue in our sinful nature and regularize our practice of sin then we are not walking in the light but rather featuring the way of life, which John calls as sin. John make a contrast in Verse 7 where he say the opposite of darkness is light, and exhorts his readers to live in the light.
