1 John 4:12 also states that loving one another makes God's love visible — directly reinforcing the test of love.

This verse positively states that love comes from God and whoever loves knows God—the opposite side of 4:20's warning about hating a brother.

1 John 3:17 likewise argues that lack of compassion for a brother shows God's love is absent — same logic.

1 John 2:4 uses the same 'liar' accusation for claiming to know God while disobeying — a direct echo of hypocrisy.

John says love for each other proves we have passed from death to life—the same test of genuine faith that 4:20 applies to loving God.

John earlier uses the same logic: claiming fellowship while walking in darkness makes you a liar—parallel to claiming love for God while hating brother.

John explicitly says loving the Father includes loving His child—supporting 4:20's claim that loving God and loving brother are inseparable.

Paul stresses that love is essential—without it, even great gifts are nothing—reinforcing John's point that love for brother proves love for God.

Peter ties sincere love for each other to obeying the truth, connecting to John's test that love for God is proven by love for others.

Peter describes loving Christ without seeing him—the same challenge John addresses, but John adds the test of loving the visible brother.

This command to love one another is the very act John says must be present to prove genuine love for God.

In Romans 12:10, believers are commanded to love one another with brotherly affection — reinforces the priority of brotherly love.

In John 13:35, love for one another is the mark of discipleship — directly supports that love for brother is evidence of love for God.

In John 5:37, Jesus says the Father's form has never been seen — reinforces the unseen God argument from 1 John 4:20.

In John 1:18, no one has seen God — echoes the same logic that love for the unseen God is proven through love for the visible brother.

In Matthew 25:42, failing to serve the needy is failing to serve Christ — parallels hating brother while claiming to love God.

In Matthew 25:40, Jesus identifies with the least, so loving a brother is loving Christ — reinforcing the inseparable link.

In Luke 11:42, Jesus condemns tithing while neglecting love of God — similar hypocrisy to claiming love for God while hating brother.

Genesis 37:4 depicts brothers hating Joseph — a concrete instance of the hatred 1 John 4:20 condemns.

Deuteronomy 10:12 commands loving God wholeheartedly — the foundation that 1 John 4:20 tests through love for brother.

2 John 1:5 echoes that this command to love one another is not new but from the beginning, reinforcing the consistency of John's teaching on love.

In John 14:15, loving Jesus means keeping his commands — obedience includes brotherly love, connecting love for God to action.

Paul models love on Christ's self-sacrifice, showing the standard that validates our love for God—a broader command than John's specific test.