God revealed Himself to the world. Two sides of the same coin. In the Old Testament, God is Holy, and sin had to have a sacrifice to have yourself cleansed to be acceptable to God. God hated sin and punished for it and gave the Law to be obeyed to avoid God's judgement. No one could completely obey the law, thus the blood sacrifices of sheep and goats.
In the New Testament, God reveals His Love and forgiveness by becoming a perfect man and dying for our sins, raising from the dead, to give us eternal life. IF we repent of our sins, acknowledge our sin and frailty, and accept Jesus into our hearts to be saved from God's judgement. Jesus living within us causes us to live better lives, and we want to give up sin to please God and be filled with His love. An unbeliever doesn't understand this, never have, never will. That is why probably only 20% of those who attend church are true Christians who actually know God.
Nothing is demanded by God, it is your belief in Jesus as Lord of Lords, and King of Kings, and acceptance of Him as your Savior that will save you. God is patient, and longsuffering waiting on those who will believe. God did demand the Jews obey Him to show that they couldn't really do it completely. So, today, if you Heed His Call, you can be saved from what is to come of the world.
The world is getting more wicked as they give up their belief in God. Murder, rape, homosexuality, abortion, stealing, lying, is running rampant, not only in America, but the world. The world needs Jesus as savior.
