In chapter 3, Paul concludes that the Law only reveals sin and that all are under guilt. The verse declares a universal truth: all have sinned and fall short of the glory of God. There are no exceptions or privileged categories before sin. The glory of God, of which we were stripped, is the standard we reach again in Christ. That diagnosis humbles human pride, but prepares the ground for grace. Only by recognizing the sickness do we receive the remedy, which is justification by faith.