The Apostle Paul loved to use contrasts to make his points about salvation and eternal life. In Romans 5:18 he said "Consequently, just as the result one trespass was condemnation for all men, so also the result of one act of righteousness was justification and brngs life for all men." 

After pausing on this subject, he took two chapters in 6 and 7 to say that we are no longer under the law (6:14) so that we might belong to another, that is Jesus (7:4).

Paul starts Romans 8 by saying "There is no condemnation for those who are in Christ Jesus." So is there then condemnation for those who are not in Christ Jesus?  To help make his point, Paul then uses many more contrast to illustrate the difference between those who are in Christ saved and those who are not lost.