To justify means to account as righteous. To justify means to make righteous. Justification comes by the imputation of Christ's righteousness.
Justification comes by an infusion of grace.
The grace of God in Christ makes the believer acceptable and pleasing in God's sight. Sanctifying grace in the believer makes him acceptable to God. God justifies the ungodly who believe. God justifies only those who are born again. Justification is God's verdict upon man in the Person of Christ.