John moves from the greatest act of love to the smallest everyday test. Few believers will be asked to die for a brother, but many will see a brother in need. If someone will not give even from his goods, what does that say about his claim to love? Barnes puts the force of the question this way: "How can a man love God who does not love those who bear his image?" Asked as a question, it leaves the reader to answer it.

John does not need to spell out the answer; it cannot dwell in him. Instead he turns the point into a call: "My little children, let us not love in word, neither in tongue; but in deed and in truth" (1 John 3:18). He adds a promise for those who do: "hereby we know that we are of the truth, and shall assure our hearts before him" (1 John 3:19).

"Bowels of compassion" is old English for the inner seat of feeling. The Greek splanchna literally means the inner organs, and Thayer's lexicon notes that the Hebrews regarded them "as the seat of the tenderer affections." To "shut up" them is to close the heart on purpose. "This world's good" translates the Greek bios, a word for life, here meaning the goods a person lives on. Gill lists them: "meat, drink, apparel, money, houses, lands."

Care for a poor brother was already in the law: "thou shalt not harden thine heart, nor shut thine hand from thy poor brother" (Deuteronomy 15:7).

This question shows that God's love is never only an idea. John has just defined love by the cross: Christ "laid down his life for us" (1 John 3:16). Love that came to us that way does not stay locked up when a brother is hungry. Barnes answers John's question with one of his own: how can anyone love God while ignoring "those who bear his image"?

Matthew Henry sees God's purpose in the needs of His people: "It pleases God that some of the Christian brethren should be poor, for the exercise of the charity and love of those that are rich." Need in the church is not an interruption of God's plan. It is one of the places where His love becomes visible.