If we say that we have fellowship uith him - If we reckon ourselves among his friends, or, in other words, if we profess to be like him: for a profession of religion involves the idea of having fellowship with God, (compare the notes at 1 John 1:3), and he who professes that should be like him.

And walk in darkness - Live in sin and error. To "walk in darkness" now commonly denotes to be in doubt about our religious state, in contradistinction from living in the enjoyment of religion. That is not, however, probably the whole idea here. The leading thought is, that if we live in sin, it is a proof that our profession of religion is false. Desirable as it is to have the comforts of religion, yet it is not always true that they who do not are not true Christians, nor is it true by any means that they intend to deceive the world.

We lie - We are false professors; we are deceived if we think that we can have fellowship with God, and yet live in the practice of sin. As God is pure, so must we be, if we would be his friends. This does not mean necessarily that they meant to deceive, but that there was an irreconcilable contradiction between a life of sin and fellowship with God.

And do not the truth - Do not act truly. The profession is a false one. Compare the notes at John 3:22. To do the truth is to act in accordance with truth; and the expression here means that such an one could not be a Christian. And yet how many there are who are living in known sin who profess to be Christians! How many whose minds are dark on the whole subject of religion, who have never known anything of the real peace and joy which it imparts, who nevertheless entertain the belief that they are the friends of God, and are going to heaven! They trust in a name, in forms, in conformity to external rites, and have never known anything of the internal peace and purity which religion imparts, and in fact have never had any true fellowship with that God who is light, and in whom there is no darkness at all. Religion is light; religion is peace, purity, joy; and though there are eases where for a time a true Christian may be left to darkness, and have no spiritual joy, and be in doubt about his salvation, yet still it is a great truth, that unless we know by personal experience what it is to walk habitually in the light, to have the comforts of religion, and to experience in our own souls the influences which make the heart pure, and which bring us into conformity to the God who is light, we can have no true religion. All else is but a name, which will not avail us on the final day.

If we say that we have fellowship - Having fellowship, κοινωνια, communion, with God, necessarily implies a partaking of the Divine nature. Now if a man profess to have such communion, and walk in darkness - live an irreligious and sinful life, he lies, in the profession which he makes, and does not the truth - does not walk according to the directions of the Gospel, on the grace of which he holds his relation to God, and his communion with him.

The Gnostics, against whose errors it is supposed this epistle was written, were great pretenders to knowledge, to the highest degrees of the Divine illumination, and the nearest communion with the fountain of holiness, while their manners were excessively corrupt.

If we say that we have fellowship with him,.... The Alexandrian copy reads, "for if we say": that is, if any profess to be partakers of the divine nature, to be like unto God, and to have communion with him, to have the light of his countenance, and the discoveries of his love:

and walk in darkness; 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 are ignorant 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:

we lie; it cannot be, it is a contradiction, the thing is impossible and impracticable; what communion hath light with darkness? or what fellowship can the throne of iniquity, or those in whom sin reigns, have with God? for God is light, and were they partakers of him, or like unto him, or had communion with him, they would consequently be in the light, and not in darkness, and much less walk in it; wherefore they are liars,

and do not the truth: they do not say the truth, nor act according to it; they do not act uprightly or sincerely, but are hypocrites, and pretend to that which they have not; and if they did the truth, they would come to the light, and not walk in darkness; see John 3:21.

If we say (ἐὰν εἴπωμεν)

The subjunctive mood puts the case as supposed, not as assumed.

Walk in the darkness

The phrase occurs only in John's Gospel and First Epistle. Darkness here is σκότος, instead of σκοτία (1 John 1:5). See on John 1:5. Walk (περιπατῶμεν), is, literally, walk about; indicating the habitual course of the life, outward and inward. The verb, with this moral sense, is common in John and Paul, and is found elsewhere only in Mark 7:5; Acts 21:21.

We lie and do not the truth

Again the combination of the positive and negative statements. See on 1 John 1:5. The phrase to do the truth occurs only in John's Gospel and First Epistle. See on John 3:21. All walking in darkness is a not doing of the truth. "Right action is true thought realized. Every fragment of right done is so much truth made visible" (Westcott).

If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:

1:6 If we... walk in darkness. To claim a fellowship with him who is Light and to walk in the darkness of error, of ignorance, and of sinfulness are utterly inconsistent.

Do not the truth. He who obeys not the truth walks in darkness.

1:6 If we say - Either with our tongue, or in our heart, if we endeavour to persuade either ourselves or others. We have fellowship with him, while we walk, either inwardly or outwardly, in darkness - In sin of any kind. We do not the truth - Our actions prove, that the truth is not in us.

6. say-profess.

have fellowship with him-(1Jo 1:3). The essence of the Christian life.

walk-in inward and outward action, whithersoever we turn ourselves [Bengel].

in darkness-Greek, "in the darkness"; opposed to "the light" (compare 1Jo 2:8, 11).

lie-(1Jo 2:4).

do not-in practice, whatever we say.

the truth-(Eph 4:21; Joh 3:21).

1:5-10 A message from the Lord Jesus, the Word of life, the eternal Word, we should all gladly receive. The great God should be represented to this dark world, as pure and perfect light. As this is the nature of God, his doctrines and precepts must be such. And as his perfect happiness cannot be separated from his perfect holiness, so our happiness will be in proportion to our being made holy. To walk in darkness, is to live and act against religion. God holds no heavenly fellowship or intercourse with unholy souls. There is no truth in their profession; their practice shows its folly and falsehood. The eternal Life, the eternal Son, put on flesh and blood, and died to wash us from our sins in his own blood, and procures for us the sacred influences by which sin is to be subdued more and more, till it is quite done away. While the necessity of a holy walk is insisted upon, as the effect and evidence of the knowledge of God in Christ Jesus, the opposite error of self-righteous pride is guarded against with equal care. All who walk near to God, in holiness and righteousness, are sensible that their best days and duties are mixed with sin. God has given testimony to the sinfulness of the world, by providing a sufficient, effectual Sacrifice for sin, needed in all ages; and the sinfulness of believers themselves is shown, by requiring them continually to confess their sins, and to apply by faith to the blood of that Sacrifice. Let us plead guilty before God, be humble, and willing to know the worst of our case. Let us honestly confess all our sins in their full extent, relying wholly on his mercy and truth through the righteousness of Christ, for a free and full forgiveness, and our deliverance from the power and practice of sin.