Our fallen nature is not sin, FK; it is a consequence of sin, a defect that is inherited through generations.
...it does not follow to me that we can take credit for the good we do
Of course not! All goodness comes from God. When we do something good, give it to God. When people thank us, accept in the name of God.
I know this is one point on which Protestants and Orthodox disagree very strongly. But even if sin is an inherited defect, how do you explain:
Rom. 6:23 : For the wages of sin is death, but the gift of God is eternal life in Christ Jesus our Lord.
I was equating "sin" with spiritual death. I see it as much more than a wounding. Do you think that "death" in this verse only refers to physical death, when the context is as plain as day?
FK: "...it does not follow to me that we can take credit for the good we do."
Of course not! All goodness comes from God. When we do something good, give it to God. When people thank us, accept in the name of God.
How can you take no credit if you were the one who chose to do a good work, using your free will? You can't believe that God moves through us, as that would thwart free will. Therefore, if you cooperate, then why do you not deserve any credit?