Paul puts together a string of Old Testament quotations to show it has always been the teaching of Scripture that all are under sin. The emphasis in the following verses is the devastating effect of sin on us. Whatever we do will be spoiled by sin. This rottenness is in our words and our actions. Human history leaves a trail of destruction like a hurricane and we too have left our own little trail. A high view of the law, realising we cannot save ourselves, leads to seeking after grace.