"For I know that nothing good dwells in me, that is, in my flesh."
Romans 7:18a
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The idea that flesh, ie physical substance, is evil is a gnostic idea. God called everything he made good and called man very good. That didn't change after Adam's fall.
Do you understand the concept of relational goodness? Compared to God, the father, nothing created of itself is good. Jesus' flesh was created.
And a certain ruler asked him, saying, Good Master, what shall I do to inherit eternal life? And Jesus said unto him, Why callest thou me good? none is good, save one, that is, God. Luke 18:18-19
There is nothing in the flesh, Jesus' included, that knows how to do the will of God. Therefore it is not good in terms of righteousness. Righteousness comes from the spirit, even for Jesus. Therefore, man walks righteously by following the spirit, not the impulses of the flesh