But if in the light we habitually walk, as He is in the light, we have fellowship with one another and the blood of Jesus Christ his Son cleanses us from all sin.1 John 1:17
Again, John rocks back and forth between contrasting ideas. Having just noted the impossibile arrangement of the Nicolaitan heresy––and others like them in history––who sought to remain in the dark and maintain their dark deeds while claiming to be in fellowship with God the light, John goes around to the contrasting arrangement: that of walking in the light.
The Greek, and in my translation I seek to bring this out, underscores that the “walking” is continual and habitual. Remaining in the light, or as John puts in His Gospel, “abiding in the vine”, is the basis for our fellowship with each other. There is no fellowship between branches which have been severed from the vine, and those still on the vine. There is unity, however, between the fruitful branches.
However––and this is a point upon which I must wave my hands vigorously so as to ensure that you not miss the point––we walk in the light “as He is in the light.” The basis for our walking in God’s light is Christ’s obedience. Being in Christ ensures that though we are dark as midnight in our sin, we have been brought into the light. This procures for us two things.
1) Fellowship with the brethren.
2) Being cleansed, by Jesus’ blood, from all our sin.
In other words, we are reconciled with our neighbor, and with our God.