God dealt with mankind by fully revealing Himself and His plan for our Salvation through Jesus Christ and the Holy Spirit.
God showing something of Himself to us is known as revelation. Sacred Scripture—the Bible—is the written account of God’s Revelation to us and describes God’s actions in the world. We know that Sacred Scripture is true because it is God’s own Word, which He made known to its writers.
God made Himself known to us in order to save us from sin. Sin caused us to lose God’s life within our very being and made us slaves to sin and subject to death. God sent His only Son, Jesus Christ, to save us from sin and death and to give us His life of grace. Because of Jesus, we can now receive God’s forgiveness for our sins, if we are really sorry and if we resolve to try not to offend Him again.