Adam Clarke's Commentary on the Bible

Verse 18 (1 John 3:18)

My little children - Τεκνια μου , My beloved children, let us not love in word - in merely allowing the general doctrine of love to God and man to be just and right;

Neither in tongue - In making professions of love, and of a charitable and humane disposition, and resting there; but in deed - by humane and merciful acts;

And in truth - Feeling the disposition of which we speak. There is a good saying in Yalcut Rubeni, fol. 145, 4, on this point: "If love consisted in word only, then love ceaseth as soon as the word is pronounced. Such was the love between Balak and Balaam. But if love consisteth not in word, it cannot be dissolved; such was the love of Abraham, Isaac, Jacob, and the rest of the patriarchs which were before them."

- Adam Clarke's Commentary on the Bible