Romans 3:19 Now we know that whatever the law says, it says to those who are under the law, that every mouth may be stopped, and all the world may become guilty before God.
Whatever the law says refers to verses 10-18 of this same chapter. All the world, whether Jewish or Gentile, stands in guilty silence before God.
No one will be declared righteous by doing what God requires in the Law. This is because the Law was not given to justify sinners but to expose sin. (From Nelson's New Illustrated Bible Commentary)
The world stands guilty before God and is in desperate need of His divine grace and redemptive intervention. It doesn't matter if we are Gentile or Jewish, black, white, brown, red, or yellow, we all stand in the same need: unless we come to Christ we will die/perish in our sins.
God bless you,