I happen to think that there is some underlying linguistic connection between 'Marcion' and 'Mark' but we will leave this aside for the moment. Let's focus instead on a line by line analysis of the material. We have reconstructed chapter 9 of the Alexandrian version of the Epistle to the Romans as:
The Law of the Spirit has freed me from the Law of sin and death. God sending his own Son in the likeness of sinful flesh has pronounced judgment upon sin in the flesh so that the Law’s ordinance might find fulfillment in us, whose lives are governed by the Spirit not by the flesh
For the carnal mind is enmity against God. The object of the flesh is death, since those whose lives are governed by the flesh follow the flesh in their objectives; and the object of the flesh is hostility to God, for it is not subject to God’s Law. Those who live on the level of flesh cannot please God for it is not subject to the law of God, neither indeed, can be. And they that are in the flesh cannot please God but you are not living by the flesh but by the Spirit, if the Spirit of God is dwelling in you. Anyone without Christ’s Spirit is not of him. But if Christ is in you, then your body is a dead thing because of sin, but the Spirit is life through righteousness. So, brothers, we are in debt. Not to the flesh, to follow it in our lives; for if you follow the flesh in the way you live, you are on the way to death. But if by the Spirit you put to death the practices of the body, you will live. For all who are guided by God’s Spirit are sons of God."
You have not received a spirit of slavery to drive you once again towards fear. You have received a Spirit that makes us sons and enables us to cry out, ‘Abba,’ ‘Father.’ For if ye live after the flesh, ye shall die. For I reckon that the sufferings of this present time are not worthy to be compared to the glory which shall be revealed in us. If we suffer with Him, that we also may be glorified together as joint-heirs of Christ. And we know that all things work together for good to them that love God, to them that are called according to the purpose. For whom He did foreknow, He also did predestinate to be conformed to the image of His Son, that He might be the first-born among many brethren. And whom He did predestinate, them He also called; and whom He called, them He also justified; and whom He justified, them He also glorified
Some interesting notes to consider about Clement's text:
Roimans 8:2 The Law of the Spirit has freed me from the Law of sin and death
The Greek is singular; and Clement is not alone in this reading. Some existing manuscripts read 'me.' Most read 'you' which brings up an interesting pattern of substitution throughout the canonical letters of Paul. I think someone systematically changed 'me' references (i.e. that the apostle was speaking about something that happened to 'him' owing to personal contact with Jesus) into 'you' references (i.e. that he was speaking generally about people being initiated into Christianity).
Also notice what else has been added in the canonical text. Our text reads:
Therefore, there is now no condemnation for those who are in Christ Jesus, because through Christ Jesus the law of the Spirit who gives life has set you free from the law of sin and death
. But the original text of Clement and (presumably) the Marcionites read:
Therefore, there is now no condemnation for those who are in Christ because the Law of the Spirit has freed me from the Law of sin and death.
Not only does the original text make a clearer Marcionite distinction between 'the law' and the 'gospel' (= the law of the Spirit) but there is the addition of 'through Christ Jesus' which follows a pattern which we already saw in Jerome's text of Gal 1:1. There we see the original Marcionite text which read:
Paul, an apostle, not from men, neither by man, but through Jesus Christ, who raised him from the dead
had the words 'and God the Father' added to obscure the apostle's relationship with Jesus:
Paul, an apostle, not from men, neither by man, but through Jesus Christ and God the Father, who raised Him from the dead
I don't know why 'through Jesus Christ' was added to Romans 8:2 but my guess is that it was designed to soften the juxtaposition between gospel and Law.