Jesus answered him, "Most assuredly, I tell you, unless one is born anew,{The word translated "anew" here and in John 3:7 (anothen) also means "again" and "from above".} he can't see the Kingdom of God."
The new birth which is here spoken of comprehends, not only what is termed justification or pardon, but also sanctification or holiness. Sin must be pardoned, and the impurity of the heart washed away, before any soul can possibly enter into the kingdom of God. As this new birth implies the renewing of the whole soul in righteousness and true holiness, it is not a matter that may be dispensed with: heaven is a place of holiness, and nothing but what is like itself can ever enter into it.