At new birth, we receive new clothes. We were all dressed in the filthy rags of sin, stained by our wrong actions but Jesus provides the robe of righteousness for us.
God wants us to use our mind, directed by Scripture and guided by the Holy Spirit, and to live our lives for His glory. This is Christian understanding.
We are no longer chained to the old life; we have been made new in Christ Jesus. This is the born again experience. God makes you a new person.
Nicodemus had everything that most men strive for authority, status, prestige, and money in the bank, but there was something missing.