Romans 8 doesn't say there is no longer any condemnation on account of our perfect conduct.
it says there isn't any condemnation because we no longer serve sin with our mind, but have died with Him to it, and serve God by our spirit. "consider yourselves dead to sin" ((Romans 6:11)) -- the first imperative statement in the whole epistle; this is a command regarding a person's thoughts.
this is not a gospel of salvation by perfect conduct. if salvation was by perfect conduct, our flesh would still condemn us before Him. Christ has made a way for us, by the cross, to be justified through faith in Him.
it says there isn't any condemnation because we no longer serve sin with our mind, but have died with Him to it, and serve God by our spirit. "consider yourselves dead to sin" ((Romans 6:11)) -- the first imperative statement in the whole epistle; this is a command regarding a person's thoughts.
For those who live according to the flesh set their minds on the things of the flesh,
but those who live according to the Spirit, the things of the Spirit.
(Romans 8:5)
I thank God — through Jesus Christ our Lord!
So then, with the mind I myself serve the law of God, but with the flesh the law of sin.
(Romans 7:25)
some people say that these two verses, barely one paragraph apart, are talking about two entirely different people, one damned and one saved. but both speak about a person whose mind is not set on the things of the flesh, but on the things of the Spirit. this is not a gospel of salvation by perfect conduct. if salvation was by perfect conduct, our flesh would still condemn us before Him. Christ has made a way for us, by the cross, to be justified through faith in Him.