Do not love in word only or tongue only

When the venerable John could no longer walk to the meetings of the Church but was borne thither by his disciples, he always uttered the same address to the Church; he reminded them of that one commandment which he had received from Christ Himself, as comprising all the rest, and forming the distinction of the new covenant, “My little children, love one another.” When the brethren present, wearied of hearing the same thing so often, asked why he always repeated the same thing, he replied, “Because it is the commandment of the Lord, and if this one thing be attained, it is enough” [Jerome]. Jamieson-Fausset-Brown Bible Commentary

This is how we know what love is: Jesus Christ laid down his life for us. And we ought to lay down our lives for our brothers and sisters. If anyone has material possessions and sees a brother or sister in need but has no pity on them, how can the love of God be in that person? Dear children, let us not love with words3056 or speech1100 but with actions and in truth. (1 John 3:16-18)

3056. logos
a word (as embodying an idea), a statement, a speech
1100. glóssa
the tongue, a language, a nation (usually distinguished by their speech)

One may love in word only, and yet the affectionate words may be quite sincere; and this is a common case. People say kind things which they mean at the moment, but afterwards they do not take the trouble to act kindly. But to love with the tongue only is far worse. This is to say kind things which one does not mean, and which one knows to be unreal. Deeds are needed to complete the kind word; truth is needed to correct the insincere tongue. Pulpit Commentary

My little children, let us not love in word, neither in tongue,…. Which though it holds good of love to God, and to Jesus Christ, yet here is to be understood of love to the brethren, as the context shows; and so the Syriac version reads, “let us not love one another in word”, &c. that is, without the heart, or with a double heart; speaking one thing with the lip, and designing another thing in the heart; speaking peaceably with the mouth, and with the heart laying wait; or we should not love in this manner “only”; and so the Arabic version of De Dieu adds. It is very lawful, and right to express our love to one another, and to all men in words, to give good words, and use courteous language, and speak in a kind, tender, and affectionate manner, and especially to persons in distress; but this should not be all, it will be of no avail to say to such, be warmed and filled, and give them nothing but these good words, nothing to warm and fill them with; see James 2:15; but in deed and in truth; for true love is a laborious and operative grace, hence we read of the work and labour of love; it shows itself by the saints serving one another, in spirituals; as by bearing one another’s burdens, forbearing with, and forgiving one another, praying for each other, and building up one another on their most holy faith; exhorting each other to the duties of religion, and not suffering sins upon one another, but admonish in love, and restore with meekness; and in temporals, distributing to the necessities of the saints, ministering: to them of their worldly substance, and supplying their daily wants: and this is loving “in deed”, or “in work”; this is actual love, love in fact, and what is apparent and evident: and it is “in truth”, when it is in reality, and not in show only; and when it is cordially and heartily done, with cheerfulness, and without grudging. Gill’s Exposition of the Entire Bible

This is how we know that we belong to the truth and how we set our hearts at rest in his presence: If our hearts condemn us, we know that God is greater than our hearts, and he knows everything. Dear friends, if our hearts do not condemn us, we have confidence before God and receive from him anything we ask, because we keep his commands and do what pleases him. And this is his command: to believe in the name of his Son, Jesus Christ, and to love one another as he commanded us. The one who keeps God’s commands lives in him, and he in them. And this is how we know that he lives in us: We know it by the Spirit he gave us. (1 John 3:19-24)

3:16-21 Here is the condescension, the miracle, the mystery of Divine love, that God would redeem the church with his own blood. Surely we should love those whom God has loved, and so loved. The Holy Spirit, grieved at selfishness, will leave the selfish heart without comfort, and full of darkness and terror. By what can it be known that a man has a true sense of the love of Christ for perishing sinners, or that the love of God has been planted in his heart by the Holy Spirit, if the love of the world and its good overcomes the feelings of compassion to a perishing brother? Every instance of this selfishness must weaken the evidences of a man’s conversion; when habitual and allowed, it must decide against him. If conscience condemn us in known sin, or the neglect of known duty, God does so too. Let conscience therefore be well-informed, be heard, and diligently attended to. Matthew Henry’s Concise Commentary