John the Apostle
1 John 3:18ESV·traditional attribution

Little children, let us not love in word or talk but in deed and in truth.

John Calvin Reformed @genevareformer

18. Let us not love in word There is a concession in this first clause; for we cannot love in tongue only; but as many falsely pretend this, the Apostle concedes, according to what is often done, the name of the thing to their dissimulation, though, in the second clause, he reproves their vanity, when he denies that there is reality except in the deed.

Matthew Henry Presbyterian @wholebiblehenry

The beloved apostle can scarcely touch upon the mention of sacred love, but he must enlarge upon the enforcement of it, as here he does by divers arguments and incentives thereto; as, I. That it is a mark of our evangelical justification, of our transition into a state of life: We know that we have passed from death to life, because we love the brethren, Jo1 3:14.

Commenting on 1 John 3:14-19

John Gill Reformed Baptist @doctorgill

And hereby we know that we are of the truth,.... By the saints loving one another in deed and in truth, they know, as the cause is known by the effect, that they are of God, who is the true God, the God of truth, and cannot lie, and is truth itself; that they are the children of God, and are born of him, since...