Therefore then, as through one trespass unto all men into condemnation, thus also through one righteousness unto all men into justification of life (Romans 5:18).
Adam’s trespass resulted in sin, bringing condemnation upon all men. In contrast, through Christ, all are justified because of His righteousness.
Christ is the last Adam, the head of righteousness (1 Corinthians 15:45). All who are in Christ are therefore righteous before God based on His righteousness, just as all who are in Adam are under condemnation because of his trespass and sin.