Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill them. I tell you the truth, until heaven and earth disappear, not the smallest letter, not the least stroke of a pen, will by any means disappear from the Law until everything is accomplished. Anyone who breaks one of the least of these commandments and teaches others to do the same will be called least in the kingdom of heaven, but whoever practices and teaches these commands will be called great in the kingdom of heaven. For I tell you that unless your righteousness surpasses that of the Pharisees and the teachers of the law, you will certainly not enter the kingdom of heaven.
God’s original standard to Adam was holiness. And, in failing that, by one man’s sin, death came to all.
God’s standard to Moses was holiness. He who broke the smallest commandment was guilty of all, and hence deserved death. He who sinned under the law deserved death, and even Gentiles, who were not aware of the law, proved that they were indeed under the law, for they demonstrate that the law itself was written on their hearts, so that their own hearts condemned them. Therefore, he who sinned with the law, and he who sinned without the law, both perished because of it, for failing to meet God’s standard. For the wages of sin is death, but the free gift of God is eternal life in Christ Jesus our Lord (Romans 6:23).
Finally, we come to the New Covenant, and for some reason, people think things have changed. And, indeed they have changed, quite a bit, but God’s desire and conditions for complete fellowship really have not.