1 John 3:18, Little children, let us not love in word or talk but in deed and truth.
Here, John is writing on the same concept as St. James, “So also faith by itself, if it does not have works, is dead” (James 2:17). Neither apostle believes works are justifying, for that belongs to the work of faith, which Christ did for us on the cross. Why bring this up, then? If two different apostles write on this to two different groups of hearers, it must be important. Clearly, Christians are not to be an actionless people. That is, we do not just proclaim the love of God to the world, but we must also do the love of God to the world. How can people believe the love of God if we, the preachers, don’t do the love of God? We believe the Word of Christ because of what He has done.
In the same way, people are more prone to believe the love of God if they see His people doing the love of God. It is human nature to take people at their word by virtue of their actions. In other words, we come to trust a person’s word because they have proven the truth of their speech by their deeds. In the same way, God’s Word does not come without action. When God speaks, He acts. Therefore, when we proclaim God’s love, we must do God’s love to our neighbour so they may see and come to believe God’s love.