Question: How can we know that we love the brethren?
The Two-Fold Answer: 1) We love God 2) We keep our Father's commandments
1 John 5:1-5; NKJV
1 Whoever believes that Jesus is the Christ is born of God, and everyone who loves Him who begot also loves him who is begotten of Him.
2 By this we know that we love the children of God, when we love God and keep His commandments.
3 For this is the love of God, that we keep His commandments. And His commandments are not burdensome.
4 For whatever is born of God overcomes the world. And this is the victory that has overcome the world — our faith.
5 Who is he who overcomes the world, but he who believes that Jesus is the Son of God?