Romans 3:9 — What then? are we better than they? No, in no wise: for we have before proved both Jews and Gentiles, that they are all under sin.
Better — should read "worse." Since Jews have privileges and still sin, are they worse? Do they deserve a greater condemnation?
Proved = legal charge, as in a courtroom
All under sin — Everyone is under the power and penalty of sin in contrast to being under grace.