Observe here, 1. That a Christian may be assured of his salvation; to know that we know, is to be assured that we know; not only to have the vital, but the fiducial act of faith. Some Christians can say, "We know that we know him."
Observe, 2. The nature of true Christian knowledge discovered: it is an obedient knowledge: it is not sufficient to profess that we know Christ, except we yield sincere obedience to him: for this is a certain mark and proof that we know Christ effectually, if we love him, and keep his commandments. The true knowledge of God consists in keeping of the word of God, the whole word of God, and because it is his.
Observe, 3. That to say we know God, when we do not keep his commandments, and to say we keep his commandments, when we do not know him, is a lie. Sad will their condition be who perish for want of the knowledge of God, but much sadder theirs, who perish in the neglect or abuse of that knowledge.
Observe, 4. That a conscientious care, and constant endeavor to observe the word, and keep the law of God, is a certain mark and evidence that he that doth it has the love of God perfected in him, and towards him; Whosoever keepeth his word, in him verily is the love of God perfected.