In Gen 4:7, the operative word is חַטָּ֣את (Chatat), lexical form: חַטָּאָה (Chatta'ah) which means: "sin, sin-offering". That is, it means either:
- Sin itself, Gen 18:20, 31:36, 50:17, Ex 10:17, 32:30, 34,, 34:7, 7, etc.
- A sin offering, Ex 29:14, 36, 30:10, Lev 4:3, 8, 14, 20, 21, etc.
The context usually determines the correct meaning.
In Gen 4:7, sin is personified as a beast waiting to pounce on Cain unless he made appropriate safeguards to resist and keep the beast of sin away. That is, חַטָּאָה (Chatta'ah) is personified temptation.
I am at a loss to understand YLT translating "sin-offering" in this instance.
Cambridge commentary notes this:
sin coucheth] The meaning is, “and, if thou doest not well and
cherishest evil in thy heart, then, remember, sin, like a savage wild
beast, is lying in ambush ready to spring out upon you.”
Ellicott is more descriptive:
We have in this verse proof of a struggle in Cain’s conscience. Abel
was evidently outstripping him in wealth; his flocks were multiplying,
and possibly his younger brothers were attaching themselves to him in
greater numbers than to Cain. Moreover, there was a more marked moral
growth in him, and his virtue and piety were more attractive than
Cain’s harsher disposition. This had led to envy and malice on the
part of Cain, increased, doubtless, by the favour of God shown to
Abel’s sacrifice; but he seems to have resisted these evil feelings.
Jehovah would not have remonstrated thus kindly with him had he been
altogether reprobate. Possibly, too, for a time he prevailed over his
evil tempers. It is a gratuitous assumption that the murder followed
immediately upon the sacrifice. The words of the Almighty rather show
that repentance was still possible, and that Cain might still recover
the Divine favour, and thereby regain that pre-eminence which was his
by right of primogeniture, but which he felt that he was rapidly
losing by Abel’s prosperity and more loving ways.