In much of modern Christianity it seems, to be almost forgotten that the gospel is the gospel of God. God sends to man His good news of His way of salvation for man. God's own nature, His truth, His holiness, His righteousness, are made known to man in His gospel.
God is light and God is love, such is His nature. His light and His love are made manifest in the cross of His Son. God cannot pass by sin. Were He to do so, He would not be the God of truth.
The cross of Christ is the great proof of His hatred of sin. His holiness can not tolerate sin in His presence, and a propitiation for all sin is made by the death of Christ. Now God declares His righteousness in His gospel concerning His Son.
The question is, will man believe God and live, or die in unbelief?
"What must I do to be saved? And they said, Believe on the Lord Jesus Christ, and thou shalt be saved." Acts 16:30, 31. "Verily, verily, [truly, truly] I say unto thee, Except a man be born again, he cannot see the kingdom of God." John 3:3.