Verse 7. But if we walk in the light. See Barnes "1 Jo 1:5".

Walking in the light may include the three following things:

(1.) Leading lives of holiness and purity; that is, the Christian must be characteristically a holy man, a light in the world, by his example.

(2.) Walking in the truth; that is, embracing the truth in opposition to all error of heathenism and infidelity, and having clear, spiritual views of truth, such as the unrenewed never have. See 2 Co 4:6; 1 Co 2:9-15; Eph 1:18.

(3.) Enjoying the comforts of religion; that is, having the joy which religion is fitted to impart, and which it does impart to its true friends, Ps 94:19; Isa 57:8; 2 Co 1:3; 13:11.

See Barnes "Joh 12:35".

As he is in the light. In the same kind of light that he has. The measure of light which we may have is not the same in degree, but it is of the same kind. The true Christian in his character and feelings resembles God.

We have fellowship one with another. As we all partake of his feelings and views, we shall resemble each other. Loving the same God, embracing the same views of religion, and living for the same ends, we shall of course have much that is common to us all, and thus shall have fellowship with each other.

And the blood of Jesus Christ his Son cleanseth us from all sin. See the sentiment here expressed fully explained See Barnes "Heb 9:11.

When it is said that his blood cleanses us from all sin, the expression must mean one of two things -- either that it is through that blood that all past sin is forgiven, or that that blood will ultimately purify us from all transgression, and make us perfectly holy. The general meaning is plain, that in regard to any and every sin of which we may be conscious, there is efficacy in that blood to remove it, and to make us wholly pure. There is no stain made by sin so deep that the blood of Christ cannot take it entirely away from the soul. The connexion here, or the reason why this is introduced here, seems to be this: The apostle is stating the substance of the message which he had received, 1 Jo 1:5. The first or leading part of it was, that God is light, and in him is no darkness, and that his religion requires that all his friends should resemble him by their walking in the light. Another, and a material part of the same message was, that provision was made in his religion for cleansing the soul from sin, and making it like God. No system of religion intended for man could be adapted to his condition which did not contain this provision, and this did contain it in the most full and ample manner. Of course, however, it is meant that that blood cleanses from all sin only on the conditions on which its efficacy can be made available to man -- by repentance for the past, and by a cordial reception of the Saviour through faith.

{b} "walk" Joh 12:35 {c} "blood" Eph 1:7; Heb 9:14; 1 Pe 1:19; Re 1:5