Justification is the legal side of salvation. Isaiah 1;16-20; even a sinner have to meet God's conditions to be saved. Romans 10:6-13. Justification gives one, access to grace. Justification gives one repentance, forgiveness, peace with God and sometimes restitution with man. Justification given one a new lease on life, through Christ. This is the legal side of salvation.
The New Birth, The New Heart, New spirit, New Creature, New man, The Spirit of Christ, the witness of the Spirit, and the divine nature (Christ), is the experimental side of justification, see Titus 3:1-11; John 3:1-8; 1 John 3rd chapter, and 2 Peter. 1:4-11
Also the Ceremonial Law, typified this experience in The Altar of Burnt Offering, The Sin Offering, The Trespass Offering, The Laver (the washing of regeneration), The Curtain (Christ the Door), the access into this grace.
The New Testament teaches that the biblical term "new birth" denotes, new life, the change that takes place in a person’s life when they are saved from sin. The old sinful ways end and a new life of righteous living begins (2 Cor 5:17). This change comes about through the Spirit of God (John 3:6-7). A person must be born of the Spirit of God in order to truly see (or understand) the kingdom of God (John 3:3; 1 Cor 2:14- 16). Being born again is also a requirement for being saved (John 3:5). The new birth denotes a life free from sin. Past sins are cleansed through repentance and faith in the blood of Jesus Christ (1 John 1:9; Rom 3:25). The new birth then enables a person to live free from sin. In fact, anyone that practices sin has not been born again (1 John 3:8-9). A person obtains a new heart (new desires) and a new spirit at the moment of conversion, a heart and spirit that knows God and in which are written his laws (Ezek 36:26-27; Jer. 24:7; Heb 8:10). The new birth involves a crucifying and putting off of the "old man", that old live of sin, (Rom 6:6; Eph 4:22) while the "new man", which is Jesus Christ, which is created in righteousness (Eph 4:24). Indeed, a person becomes an entirely new creation (Eph 2:10).