For God so loved the world, that he gave his only begotten Son, that whosoever believes in him should not perish, but have everlasting life. For God sent not his Son into the world to condemn the world; but that the world through him might be saved. (John 3:16-17)
The most often quoted verse in the Bible contains the whole of the gospel, and in it, is revealed the heart of God. The motive of God in giving us Christ was love. Jesus Christ came to SAVE us from our sins – not condemn us for our sins. But you will note that this Truth of the gospel will be nonsense to me if I don’t believe that I NEED to be saved from my sins – or if I think I can do something to save myself. This is why the good news of Jesus Christ must always contain the bad news about our condition before God. The sinner must see his need or else the gospel will be to him nothing more than a religion.
So often, the gospel is presented as, “a threat of punishment.” The mantra is often, “believe in Jesus or be sent to hell!” But this is silly because we are already dead spiritually – we might even say that we are already in a hell of sorts, because in Adam we are separated from God. So it is not so much a matter of God punishing us if we don’t believe. It is a matter of us refusing life and sealing our death: “He that believes on him is not condemned: but he that believes not is condemned already, because he has not believed in the name of the only begotten Son of God.” (John 3:18)
If we won’t believe, God will simply judge us to be worthy of our choice.
God is not the author of death. Jesus Christ is the life, and the refusal of him is death. But none of that is necessary. Jesus Christ has already finished everything necessary for each of us to be saved. He died for all – not just an elect few. Why? Because God so LOVED the world – this is why He gave His only begotten Son.