1 John 3:19

And hereby we know. Important textual evidence may be cited (cf. p. 10) for the omission of “and,” thus bringing the verse into harmony with John’s usual construction (cf. on v. 16). Textual evidence also favors the reading “we shall know.” Unlike the similar constructions in vs. 10, 16; ch. 2:3, this “hereby” appears to refer back to the preceding verse (v. 18), and the writer implies that when the precept there enunciated is practiced, we shall gain that conviction of which he speaks. When we love in deed and truth, we receive an assurance of the reality of our conversion. Thus our own fruits inform us as to the genuineness of our profession even as the lives of others witness to their sincerity (Matt. 7:16-20).

Of the truth. Compare the reference to “truth” in v. 18. Those who love in deed and truth are children of truth.

Assure. Greek peithō, here, either “to persuade” or “to set at ease.” The conviction that we are born of God gives a confidence that sets the heart at rest and enables us to come to God in spite of our sinfulness.

Our hearts. Important textual evidence may be cited (cf. p. 10) for the reading “our heart,” as in v. 20. The use of the singular in Greek is idiomatic. Here, the heart may be taken for the conscience (cf. on Matt. 5:8).

Before him. That is, before God, or in the presence of God. It is comparatively easy to reassure one’s own heart when the examination is conducted in the light of human standards; but it is another matter to stand in the presence of God and still have a tranquil heart. Yet John assures us it can be done. The nearer we come to God, the more conscious we become of our own imperfections and the more need we have to recite the many reasons why we must trust in our Saviour’s merits (see ch. 2:1, 2). Thus because we love the brethren in deed and in truth, we know that we are of the truth, and because we are of the truth, we may stand fearlessly before our heavenly Father.