3 And hereby we do know that we know him, if we keep his commandments.   4 He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him.   5 But whoso keepeth his word, in him verily is the love of God perfected: hereby know we that we are in him.   6 He that saith he abideth in him ought himself also so to walk, even as he walked.

      These verses may seem to relate to the seventh verse of the former chapter, between which and these verses there occurred an incidental discourse concerning the believer's duty and relief in case of sin, occasioned by the mention of one of the believer's privileges--his being cleansed from sin by the Mediator's blood. In that verse the apostle asserts the beneficial consequence of walking in the light: "We have then fellowship with one another, such divine fellowship and communion as are the prerogative of the church of Christ." Here now succeeds the trial or test of our light and of our love.

      I. The trial of our light: And hereby we do know that we know him, if we keep his commandments, v. 3. Divine light and knowledge are the beauty and improvement of the mind; it becomes the disciples of the Mediator to be persons of wisdom and understanding. Young Christians are apt to magnify their new light and applaud their own knowledge, especially if they have been suddenly or in a short time communicated; and old ones are apt to suspect the sufficiency and fulness of their knowledge; they lament that they know God, and Christ, and the rich contents of his gospel, no more: but here is the evidence of the soundness of our knowledge, if it constrain us to keep God's commandments. Each perfection of his nature enforces his authority; the wisdom of his counsels, the riches of his grace, the grandeur of his works, recommend his law and government. A careful conscientious obedience to his commands shows that the apprehension and knowledge of these things are graciously impressed upon the soul; and therefore it must follow in the reverse that he that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him, v. 4. Professors of the truth are often ashamed of their ignorance, or ashamed to own it; they frequently pretend to great attainments in the knowledge of divine mysteries: Thou makest thy boast of God, and knowest his will, and approvest (in thy rational judgment) the things that are more excellent, being instructed out of the law and art confident that thou thyself art (or art fit to be) a guide to the blind, &c., Rom. ii. 17, &c. But what knowledge of God can that be which sees not that he is most worthy of the most entire and intense obedience? And, if that be seen and known, how vain and superficial is even this knowledge when it sways not the heart unto obedience! A disobedient life is the confutation and shame of pretended religious knowledge; it gives the lie to such boasts and pretences, and shows that there is neither religion nor honesty in them.

      II. The trial of our love: But whoso keepeth his word in him verily is the love of God perfected; hereby know we that we are in him, v. 5. To keep the word of God, or of Christ, is sacredly to attend thereto in all the conduct and motion of life; in him that does so is the love of God perfected. Possibly, some may here understand God's love to us; and doubtless his love to us cannot be perfected (or obtain its perfect design and fruit) without our practical observance of his word. We are chosen, to be holy and blameless before him in love; we are redeemed, to be a peculiar people, zealous of good works; we are pardoned and justified, that we may be partakers of larger measures of the divine Spirit for sanctification; we are sanctified, that we may walk in ways of holiness and obedience: no act of divine love that here terminates upon us obtains its proper tendency, issue, and effect, without our holy attendance to God's word. But the phrase rather denotes here our love to God; so v. 15, The love of (to) the Father is not in him; so ch. iii. 17, How dwelleth the love of (to) God in him? Now light is to kindle love; and love must and will keep the word of God; it enquires wherein the beloved may be pleased and served, and, finding he will be so by observance of his declared will, there it employs and exerts itself; there love is demonstrated; there it has its perfect (or complete) exercise, operation, and delight; and hereby (by this dutiful attendance to the will of God, or Christ) we know that we are in him (v. 5), we know that we belong to him, and that we are united to him by that Spirit which elevates and assists us to this obedience; and if we acknowledge our relation to him, and our union with him, it must have this continued enforcement upon us: He that saith he abideth in him ought himself to walk even as he walked, v. 6. The Lord Christ was an inhabitant of this world, and walked here below; here he gave a shining example of absolute obedience to God. Those who profess to be on his side, and to abide with him, must walk with him, walk after his pattern and example. The partisans of the several sects of philosophers of old paid great regard to the dictates and practice of their respective teachers and sect-masters; much more should the Christian, he who professes to abide in and with Christ, aim to resemble his infallible Master and head, and conform to his course and prescriptions: Then are you my friends if you do whatsoever I command you, John xv. 14.