Jesus spoke about new birth
Jesus used the phrase when Nicodemus, a respected religious teacher, came to speak with him at night. Nicodemus knew the Scriptures and took faith seriously, yet Jesus told him that seeing God's kingdom required a birth from above, a work only God can do (John 3:3-5).
Nicodemus first heard Jesus in very literal terms and was confused. Jesus explained that physical birth and spiritual birth are different. The Spirit gives this new life, and although we cannot control or fully trace his work, its reality becomes evident, much like the wind that can be heard and felt (John 3:6-8).
Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
It begins with trusting Christ
Being born again is not a prize for people who have cleaned up their lives. Paul says salvation comes by God's grace, received through faith, not earned by our works (Ephesians 2:8-9). That leaves no room for pretending we can save ourselves, but it gives real hope to anyone who comes to Jesus.
Jesus points people to faith in him as God's Son, the one sent in love for the world (John 3:16-18). To trust him means turning to him honestly, relying on his death and resurrection rather than on your own record. John describes those who receive Christ as becoming God's children, born because of God's action rather than human effort (John 1:12-13).
For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast.
God makes a person new
New birth does not mean a Christian instantly becomes flawless. Christians still need to confess sin, learn, forgive, and grow. But God gives a new direction, new desires, and a new relationship with him. Paul describes the person who belongs to Christ as a new creation, with the old life no longer having the final word (2 Corinthians 5:17).
Titus says this renewal is connected with God's mercy and the Holy Spirit, not with righteous deeds we have done to impress God (Titus 3:5). So a born again Christian is not someone claiming moral superiority. They are someone who has received mercy and is learning to live from it.
What might it look like day by day?
The change often shows up over time. A person may find a growing desire to know God, a sharper awareness of sin, a willingness to repent, and a deeper love for others. Peter connects new birth with a living hope through Jesus' resurrection, and with a love that comes from a changed heart (1 Peter 1:3; 1 Peter 1:22-23).
If you are wondering whether this is true of you, start with Jesus rather than trying to measure every feeling. Bring him your trust, questions, failures, and hopes. Keep reading the Gospels, and ask God to help you understand and follow Christ. New life is his gift, not a performance you have to manufacture.
Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.