The love I speak of is...the love he showed to us in sending his Son as the remedy for the defilement of our sins. 1 John 4:10, N.E.B.
Hippocrates said, "Extreme remedies are very appropriate for extreme diseases." In other words, you do not apply a Band-aid to someone who has just had open-heart surgery.
As Christians, we talk a lot about getting rid of sin in our lives. We rejoice that the blood of Jesus covers our sins. But what are we really saying? More important, what do we believe regarding the atoning sacrifice of Christ? To conceive of the death of Christ as a way to appease an angry God is to diminish the whole process of redemption. It makes Jesus a divine Band-Aid over the "new-heart surgery" God is performing for each of us.
The way in which we view sin determines how we approach the Surgeon. If sin is bad behavior, we come expecting Him to replace it with better behavior. Unfortunately, as in the case of literal open-heart surgery where harmful habits caused degeneration, corrective surgery isn't enough. Even as physical health is ensured only with a lifestyle change, "new-heart surgery" is successful only to the degree our opinion of God has changed.
Our God saw as appropriate in dealing with the disease of sin the extreme remedy of sending "his only Son into the world to bring us life." Notice: "And his love was disclosed to us in this" (1 John 4:9, N.E.B.). May I propose an important clarification? It was the love revealed in the sending of the Son, not the physical death of Christ on the cross, that was the primary remedy. "The love I speak of is...the love he showed to us in sending his Son as the remedy for the defilement of our sins" (verse 10).
Let me explain further. In Hebrews 3:12, Paul counsels, "Take care, brethren, lest there be in any of you an evil, unbelieving heart, leading you to fall away from the living God" (R.S.V.). Unbelief in God is what makes the heart evil--not unbelief that He is, but unbelief in who He is. It would do no good at all to remove the results of that unbelief from our lives (sin) if we retain the hurtful opinion of God that is causing the problem in the first place! Therefore, God showed us Himself in His Son. He showed us all that we need to change our minds about Him.
That is the "new-heart surgery"!