Chizuk Emunah (Pt 2) Under the Microscope: Chapter 77

Romans 5:14, "Nevertheless death reigned from Adam to Moses, even over them that had not sinned after the similitude of Adam's transgression."
Other copies have the contrary. "Who had sinned after the similitude," etc.

If death reigned to the days of Moses only, how is the question to be explained: How could Jesus be considered the Saviour of mankind, if the dominion of death had been made to cease through the laws of Moses, (Lev 18:5) "which, if a man performeth, he liveth in them?" See the question fully discussed in chapter one of the First Part of this work.

As Moses writes:

You shall follow my rules and keep my statutes and walk in them. I am the LORD your God. You shall therefore keep my statutes and my rules; if a person does them, he shall live by them: I am the LORD.
(Leviticus 18:4-5)

And Paul writes regarding sin and death in Adam:

Therefore, just as sin came into the world through one man, and death through sin, and so death spread to all men because [of which] all sinned—for sin indeed was in the world before the law was given, but sin is not counted where there is no law. Yet death reigned from Adam to Moses, even over those whose sinning was not like the transgression of Adam, who was a type of the one who was to come.

But the free gift is not like the trespass. For if many died through one man's trespass, much more have the grace of God and the free gift by the grace of that one man Jesus Christ abounded for many. And the free gift is not like the result of that one man's sin. For the judgment following one trespass brought condemnation, but the free gift following many trespasses brought justification. For if, because of one man's trespass, death reigned through that one man, much more will those who receive the abundance of grace and the free gift of righteousness reign in life through the one man Jesus Christ.

Therefore, as one trespass led to condemnation for all men, so one act of righteousness leads to justification and life for all men. (Romans 5:12-18)

 Paul never asserts that death's reign ended in the days of Moses. He said that even without the Mosaic Law, death still reigned. One does not need the Law in order for there to be condemnation for sin, lest anyone argue that we were fine until we were given the Law. It is a given that death reigned since Moses; Paul is merely arguing that death reigned before Moses as well.

This is a different look at sin than Paul learned in his Jewish background. Paul's upbringing would have told him that the problems began when Israel started disobeying the Law given at Sinai. Paul is now arguing that the problem with sin began not with disobeying Moses, but with Adam himself.

The promise of Leviticus is explained in detail in Deuteronomy 28. Eternal life is not promised as a reward for keeping God's commandments. I agree with rabbis like Asher Meza who argue that there is no mitzvah to go to heaven. The commands of Moses have nothing to do with going to heaven after you die. They are commands for the nation of Israel, where God would dispense earthly and political blessings for the nation for obedience, as well as pain and exile for disobedience. It is in this sense that by keeping the commandments you will live. Your nation will see prosperity, and your people will not be victims of ethnic cleansing.

One might also argue that the death mentioned is spiritual death rather than physical death. This is unlikely given the parallel in 1 Corinthians:

For as by a man came death, by a man has come also the resurrection of the dead. For as in Adam all die, so also in Christ shall all be made alive.
 (1 Corinthians 15:21-22) 

This is the death of which Paul speaks. It is the death of our bodies, and our lack of hope if we do not have resurrection.