The translation of 1 John 3:4 by the KJV is "Sin is transgression of the law" is most unfortunate. The Greek phrase is just
ἡ ἁμαρτία ἐστὶν ἡ ἀνομία = "sin is lawlessness"
However, the KJV rendering is more theological that translational and thus is not entirely without foundation, but not in 1 John 3:4. For example:
- Rom 3:20 - ... for through the Law is knowledge of sin.
- Rom 7:7 - Nevertheless, I would not have known what sin was had it not been for the law. For I would not have known what coveting really was if the law had not said, "You shall not covet."
- Rom 7:13 - Did that which is good, then, become death to me? Certainly not! But in order that sin might be exposed as sin, it produced death in me through what was good, so that through the commandment sin might become utterly sinful.
That is, without the law (moral law is obviously referenced here) we do not know that we are sinful! That is, the law defines sin but offers no remedy.
In Rom 6:15 Paul appears to be addressing a common problem that has plagued Christianity from the beginning, a problem Paul and other address in other places - the problem of licentiousness. This idea is known in some circles as "cheap grace" (see https://www.gotquestions.org/cheap-grace.html ) - because God is so kind and forgiving we can sin all we like and God will always forgive.
- Rom 6:15 - What then? shall we sin, because we are not under the law, but under grace? God forbid.
- Rom 6:1, 2 - What then shall we say? Shall we continue in sin so that grace may increase? Certainly not!
- Rom 3:31 - Do we, then, nullify the law by this faith? Certainly not! Instead, we uphold the law.
- Jude 4 - ... They turn the grace of our God into a license for immorality ...
Barnes succinctly summarizes the problem that Paul deals with in Rom 6:15 -
What then? shall we sin ... - The apostle proceeds to notice an
objection which might be suggested. "If Christians are not under the
law, which forbids all sin, but are under grace, which pardons sin,
will it not follow that they will feel themselves released from
obligation to be holy? Will they not commit sin freely, since the
system of grace is one which contemplates pardon, and which will lead
them to believe that they may be forgiven to any extent?" This
Consequence has been drawn by many professing Christians; and it was
well therefore, for the apostle to guard against it.
Similarly, Gill suggests -
because we are not under the law, but under grace? here the apostle
meets with an objection of the adversary, saying, that if men are not
under the law, and are free from all obligation to it, then they may
live as they list; nor can they be chargeable with sin, or that be
objected to them; since where there is no law, there is no
transgression, and sin is not imputed where there is no law; and if
they are under grace, or in the love and favour of God, from which
there is no separation, then they cannot be damned, do what they will:
but this objection proceeds upon a mistaken sense of the phrase,
"under the law"; for believers, though they are not under the law as
the ministry of Moses, yet they are under it, as it is in the hands of
Christ; and though not under its curse, yet under obligation to
obedience to it, from principles of love and grace; and a
transgression of it is sin in them, as in others; and which is taken
notice of by God, and visited with stripes in a: fatherly way, though
his loving kindness is not removed: and to argue from the
unchangeableness of God's grace, or the doctrines of it, as
encouraging licentiousness, is greatly to abuse the grace of God, and
manifestly betrays such persons to be ignorant of it and its
influence; since nothing more powerfully engages to a love of
holiness, and hatred of sin; wherefore the apostle, answers to this
objection in his usual way,
God forbid; signifying his abhorrence of everything of this kind.
Mosaic Law vs Moral Law
The OP specifically askes about the Mosaic law. The law in view in Rom 6, 7 , 13 etc, is the Moral law as signified by the following considerations.
- Rom 13:9 - The commandments “Do not commit adultery,” “Do not murder,” “Do not steal,” “Do not covet,” and any other commandments, are summed up in this one decree: “Love your neighbor as yourself.” [These are all from the Moral Law of the 10 commandments, not the ceremonial Law.]
- Rom 7:7 - What then shall we say? Is the law sin? Certainly not! Indeed, I would not have been mindful of sin if not for the law. For I would not have been aware of coveting if the law had not said, “Do not covet.” [Again, this is an extract of the Moral Law of the 10 commandments.]
Further, this moral law cannot be called the Mosaic law because it existed well before Moses [Moses was the first to formally have it recorded]. Note the following examples of the Moral Law existing well before Moses:
The following (far from exhaustive) list shows that people knew of the ten commandments well before the formal giving at Mt Sinai. Indeed, we have the very general comment –
- Gen 26:5, because Abraham listened to My voice and kept My charge, My commandments, My statutes, and My laws.
Commandment #1 – Worship only YHWH:
- Gen 22:5, 24:26, 48, 52 all describe worship of the true God of heaven, YHWH.
- Gen 35:1-4 – Jacob instructs his whole household to eliminate all foreign gods
Commandment #2 – Idolatry prohibited
- Gen 31:32-35 – Jacob clearly understood that idolatry was forbidden.
- Gen 35:1-4 – Jacob instructs his whole household to eliminate all foreign gods
Commandment #3 –Cursing and taking the name of the LORD in vain prohibited
- Job 1:5 – When these celebrations ended—sometimes after several days—Job would purify his children. He would get up early in the morning and offer a burnt offering for each of them. For Job said to himself, “Perhaps my children have sinned and have cursed God in their hearts.” This was Job’s regular practice.
Commandment #4 – Sabbath worship
- Gen 2:1-3 – Thus the heavens and the earth were completed in all their vast array. And by the seventh day God had finished the work He had been doing; so on that day He rested from all His work. Then God blessed the seventh day and sanctified it, because on that day He rested from all the work of creation that He had accomplished.
- Gen 16 also records the incident with manna and that collecting manna on the seventh-day Sabbath was forbidden
Commandment #5 – Respect for parents, elders and authority
- Gen 28:6, 7 tells of the story of Jacob following his mother’s advice. Respect for parents is built into the very fabric of the patriarchal stories in Genesis.
Commandment #6 – Sanctity of Human life
- Gen 4:8-12, 15 records Cain’s punishment for the sin of murder
- Gen 9:5, 6 records that murder was prohibited under the ancient Noahide covenant
Commandment #7 – Adultery prohibited
- Gen 12:10-20, 20:1-17, 26:6-11 all record “adultery narratives” in which the patriarch is (correctly) chided for almost tricking a pagan king into committing adultery
- Gen 19 records the appalling events involving attempted pack-rape of the two angels
- Gen 39:7-9 – Joseph calls Potiphar’s wife proposal “a great evil and sin against God”.
- Gen 49:4 – Reuben is scalded for his sin of incest
- Gen 34 – the story of Dinah records a heinous incident involving her defilement (plus murder and lying)
Commandment #8 – Stealing prohibited and respect for property
- Gen 30:33 – Laban and Jacob discuss the problem of stealing of wages and property
- Gen 31:32-35 – Laban is angry about the sin of stealing the household gods
Commandment #9 – Lying prohibited; insistence of honesty and integrity
- Gen 4 – the story of Cain being punished, among other things for not being honest with Abel and God in his statements
- Gen 12:10-20, 20:1-17, 26:6-11 all record “adultery narratives” in which the patriarch is (correctly) chided for lying to a pagan king about their marital status
- In the story of Jacob, he is pejoratively called Jacob = “deceiver”, Gen 27:36.
Commandment #10 – Coveting prohibited
- Gen 3:6 – the woman is tricked by the serpent using the sin of covetousness