What are plural "sins" in relation to old Adam?
Plural sins are the fruit of old Adam—the things old Adam causes us to do. In Romans, singular sin refers to old Adam himself, the fountainhead and Adamic sinful nature, while plural sins are the outward deeds produced by that nature.
Les explains that throughout Romans he uses the term old Adam in place of the singular word sin, because that is what Paul is really talking about. He says old Adam is the fountainhead of all our problems and the Adamic sinful nature. The fruit of old Adam are the things we do, which are sins, S-I-N-S, plural. So sin, singular, usually refers to old Adam, while sins, plural, are the things old Adam causes us to do. Les also connects this to verse 3, where God sent His Son in the likeness of sinful flesh and for sin, to take the place of old Adam so believers could be crucified with Him, with old Adam condemned in the flesh.
More Questions
What does the plural word 'sins' mean in Paul's writings?
Plural 'sins' in Paul's teaching are the fruit of old Adam—the things that old Adam causes us to do.