I think John is my favorite Apostle; he is so deep on the one hand and so simple and direct on the other that he makes tough theology so obvious.
How is a person born again, and why should we love our brother and sister in the Lord? John nails these two questions down in one sentence:
Everyone who believes that Jesus is the Christ is born of God, and everyone who loves the father loves his child as well.
So, we are born again if we believe that Jesus is the Christ; we are now born of God. Then he goes further to add that if we love the Father we must also love His children. So simple! Then the next sentence makes it even more clear:
This is how we know that we love the children of God:by loving God and carrying out his commands. (v. 2)
Any particular command that comes to mind? How about “Love one another!”
But wait! There’s another sentence after this:
This is love for God: to obey his commands. (v. 3)
Just in case anybody missed it, he adds this: To love God is to obey Him, to obey Him is to love Him… therefore we must love each other, for this is His command.
What comes next is nothing less than pure communication genius:
And his commands are not burdensome, for everyone born of God overcomes the world. This is the victory that has overcome the world, even our faith. Who is it that overcomes the world? Only he who believes that Jesus is the Son of God.
He takes his argument right back to his original statement about believing that Jesus is the Christ and being born of God! So, since we are born again if we believe this, and if we are born again we must love the Father and His Son and be commanded to love one another, we have therefore overcome the world and the burden of obedience is light!
How can anybody not just love John to death? He took a 500 page text-book and explained the whole thing in six short, choppy sentences!
If you ever need to explain the whole foundation of the Christian life, remember 1 John 5:1-5.