"For all have sinned and fall short of the glory of God"
In Romans 3:23, Paul describes a doctrinal truth necessary to understanding salvation by grace through faith. He explains that all individuals regardless of their heritage fail to meet the perfect standard of righteousness required by God indicating the need for punishment without the imputed righteousness of Christ.
The message in the verse is clear: everyone has sinned and will continue to sin—as implied by the use of present tense in the original Greek language; and sin disqualifies its participants from the glory of God. After laying this foundational truth, Paul then builds the case for justification by grace through faith in Christ in the subsequent verses.