Jesus reveals in John 14:20, "In that day, you will know that I am in the Father, you are in me, and I am in you." This is the heart of the Gospel. Through the blood of Christ and the power of the Holy Spirit, there is no separation between us and God.
Created in His image, we misused our freedom and became a mess, blind to our Father's love. We even killed Jesus, our Creator. Yet, God raised Him from the dead and, instead of vengeance, offered grace. In our darkest moment, He redeemed us. When you realize how unfair this is, gratitude is our only remaining option.
Even Jonathan Edwards realized late in life: "we contribute nothing to our salvation but the sin that made it necessary." The Gospel is simple—God finds us in our lostness and saves us by His grace alone.