expression
retribution for one's crime; punishment for one's crime
A set phrase meaning the natural consequence or punishment that comes from committing a crime or wrongdoing. Often used in moral or religious contexts.
彼は罪の報いを受けることになった。
He ended up receiving retribution for his crime.
罪の報いは必ず来ると信じている。
I believe that punishment for one's crime will surely come.
A compound of 罪 (crime) + の (possessive particle) + 報い (reward, retribution). The phrase is a straightforward combination of its parts and does not have a complex historical derivation.