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

If we walk in the light ... When the light from God, as revealed in Christ Jesus and the preaching of the apostles, is entered and walked in by the Christians, "Walking in the light shows up their sins and frailties, revealing the need for constant cleansing."[32]

Roberts pointed out that John's teaching here "implies that only the sinless can have fellowship with a sinless God," adding that this involves a contradiction between our own "admitted sinfulness and the affirmation that we do have fellowship with God (1 John 1:3)."[33] Roberts resolved the "contradiction" in the considerations of: (1) Christ's propitiation for our sins; (2) the cleansing action in view in this verse; and (3) the intercession on our behalf of Jesus Christ our advocate. Here indeed is the achievement of that absolute perfection required of all who hope to enter heaven, as announced by Jesus Christ in the sermon on the mount (Matthew 5:48). The whole doctrine of Perfection requires a great deal more attention to it than is evident in current Christian literature. For a further study of it, see in my Commentary on Galatians, pp. 130-133. For those who walk in the light, the continual, ceaseless and effective cleansing through the blood of Christ is the means of their continuing in a state of absolute perfection. This cleansing, however, is not necessarily automatic. "It is based upon confession, penitence, renewal (1 John 1:9), and keeping his commandments (1 John 2:3)."[34] Even beyond this, however, the cleansing effect of Jesus' blood is operative unconditionally in instances of the believer's unawareness of sins that lie hidden from himself.

Fellowship one with another ... Although not stated in this sentence, this fellowship is also with God the Father and his Son Jesus Christ (1 John 3). This fellowship stands for membership in the corporate spiritual body of Jesus Christ. Thus the cleansing here mentioned is not that from "old sins" prior to conversion, but from the accrual of sins daily by the Christian.

The blood of Jesus his Son ... All forgiveness for mortals, in the last analysis, derives from this source. John's mention of it so early in the epistle shows the high priority of this fundamental truth.

Cleanseth us from all sin ... "The singular sin sometimes denotes the principle of sin, but this cannot be the meaning here. All sin means `every act of sin.'"[35]

This great verse is the source of incredible joy, assurance and consolation to the child of God. He never needs to fear that some impulsive, unintentional, or atypical conduct might overtake him with the result of eternal condemnation. His walking "in the light" can be established by the long term directional thrust of his whole life upon earth and cannot be contradicted and negated by any temporary or insignificant lapse.

[32] Charles C. Ryrie, Wycliffe Bible Commentary, New Testament (Chicago: Moody Press, 1971), p. 1007.

[33] J. W. Roberts, op. cit., p. 31.

[34] Ibid., p. 32.

[35] Leon Morris, op. cit., p. 1262.