Response
We can understand Romans 5:13 and Romans 7:8 without any contradiction if we let in Romans 7:9 and Romans 2:12 to clarify the meaning.
According to Rom 2:12, some people (majority) sin without law and some (minority) sin within law. When the same people sin without law, that sin, according to Rom 7:8, is dead because “apart from law sin is dead”.
Why is sin dead, apart from law?
It is because, according to Rom 5:13, “sin is not charged (by God) when there is no law”.
But why doesn’t God charge sin to the offender?
It is because God wants to show mercy later as “being ignorant” they “did it (sin) in unbelief” (1 Tim 1:13).
As long as God doesn’t charge sin to them, they are “alive apart from law”, according to Rom 7:9. [However, this physical life has nothing to do with the “abundant life” (John 10:10) promised by Jesus Christ]
But today or tomorrow, everyone (dead or alive) will hear the Gospel from God. At that time, ‘the commandment will come, and sin will come alive, and they will die’ (spiritually), according to Rom 7:9.
“And I was alive apart from Law once, but the commandment came, and sin came alive, and I died” (Rom 7:9).
Then a new life (new creation) in Christ will begin for the new believer (2 Cor 5:17).
Explanation
Paul is to the New Testament what Moses is to the Old Testament. Both have deeper aspects to what is apparent on the surface. So a logical (“rightly”) “dividing” of the Scripture (2 Tim 2:15) is advised. Let us do that here.
Rom 5:13 says:
“sin was in the world until the law”.
But the real question is: can sin exist without the law?
The answer is: no, because “sin is the transgression of the law” (1 John 3:4).
So, when there is no law to transgress, there cannot be sin. In other words, sin cannot exist without law because law is required to define sin (Rom 7:7)!
However, the question remains: then what does Rom 5:13 mean?
Logically it means “sin was in the world until the law” was known publicly to people. Humanity at large didn’t know about the spiritual law of God because He hadn’t given it yet to Israel or others publicly.
How Law worked until Sinai
- When Cain began to hate Abel, God told him:
“And if you do not do well, SIN is crouching at the door; and its
desire is toward you; but you should rule over it” (Gen 4:7).
We now know that sin is the breakage of law. So, what law was Cain going to break?
“Thou shall not murder”.
God knew that Cain “glowed greatly with ANGER” (verse 5) towards his own brother. This was the beginning of his hatred against Abel. (Anger may lead to murder)
The same God said later:
“You have heard that it was said to the ancients: "Do not commit
murder!" And, Whoever commits murder shall be liable to the Judgment.
But I say to you, Everyone who is ANGRY with his brother without
cause shall be liable to the Judgment” (Mat 5:21-22). (Anger may lead
to murder).
Thus, we have seen that the “sin” God warned Cain against was the breakage of the law: thou shall not murder!
But the secular “world” seriously didn’t know about this law until it was given at Sinai.
- Patriarch Joseph and “sin against God” (Gen 39:9).
Potiphar’s wife had a desire for Joseph because he was very handsome (verse 6). She invited him several times but “he refused” (verse 8).
See what he replies to her:
“No one in this house is greater than I, and he (Potiphar) has not
withheld anything from me except you, because you are his wife. And
how should I do this great evil and SIN against God?” (verse 9).
Note well; Joseph didn’t say ‘sin against Potiphar’ but “sin against God”!
Question: which law Joseph didn’t want to break?
Answer: “Thou shall not commit adultery”
These two examples are enough to show that before Sinai, God revealed His law only to selected Patriarchs in the Old Testament. But God’s law was existing in reality but it was not known publicly to the “world”.
[A rough analogy: until Isaac Newton explained mathematically, the world at large was not knowledgeable enough about the law of Gravity. But the real gravity law was operational right from the creation of the universe!]
See what God testifies about Patriarch Abraham:
“Abraham obeyed my voice (qol), and kept my charge (mishmereth),
my commandments (mitzvah), my statutes (chuqqah), and my laws (torah)”
(Gen 26:5).
Conclusion
“For God has shut up ALL (except the “little flock” – Luke
12:32) in unbelief (they either do not believe in God’s law or
they think God’s law is nailed to the cross), so that He might show
mercy to ALL” (Rom 11:32).
“But the Scripture shut up ALL (except the “little flock” – Luke
12:32) under sin, so that the promise by faith of Jesus Christ might
be given to those who believe” (Gal 3:22).
So, the Law that defined sin was already operational right from the Garden of Eden. But it was not publicly given by God until it was given to Israel at Mount Sinai. Prior to that, only holy men of God knew it and kept it.
The world at large didn’t know about it. To them God didn’t charge sin and hence their sin was dead and they were alive for a time.
God reveals His law through His Gospel (Rom 7:9).
When the law is revealed, then God “charges sin” to the believer and he becomes dead (Rom 7:9). Here Jesus’ sacrifice and holy blood “justifies” him and he becomes a “new creation” (2 Cor 5:17).
A new life starts!