Charles Spurgeon Commentary 1 John 4:9

"Herein was the love of God manifested in us, that God hath sent his only begotten Son into the world that we might live through him." — 1 John 4:9 (ASV)

In this was manifested the love of God toward us, because that God sent his only begotten Son into the world, that we might live through him.

There is love in our creation; there is love in providence; but most of all there is love in the gift of Christ for our redemption. The apostle here seems to say, "Now that I have found the great secret of God's love to us; here is the clearest evidence of divine love that ever was or ever can be manifested toward humankind."

In this was manifested the love of God toward us, because that God sent his only begotten Son into the world that we might live through him.

That was the highest possible proof of love that even God could give us.