In this the children of God are revealed, and the children of the devil. Whoever doesn’t do righteousness is not of God, neither is he who doesn’t love his brother.
children of the devil--(See on Jo1 3:8; Act 13:10). There is no middle class between the children of God and the children of the devil. doeth not righteousness--Contrast Jo1 2:29. he that loveth not his brother-- (Jo1 4:8); a particular instance of that love which is the sum and fulfilment of all righteousness, and the token (not loud professions, or even seemingly good works) that...
10 In this the children of God are manifest. He shortly draws this conclusion, that those in vain claim a place and a name among the children of God, who do not prove themselves to be such by a pious and holy life, since by this evidence they shew that they differ from the children of the devil.
The apostle, having alleged the believer's obligation to purity from his hope of heaven, and of communion with Christ in glory at the day of his appearance, now proceeds to fill his own mouth and the believer's mind with multiplied arguments against sin, and all communion with the impure unfruitful works of darkness. And so he reasons and argues, I.
Commenting on 1 John 3:4-10