“In the mid-1970s, Charles Colson, an adviser to President Nixon who became embroiled in the Watergate scandal, was converted to Christ and wrote a book titled Born Again, which sold millions of copies. A few years later, President Carter revealed that he was a “born-again Christian.” Suddenly, the words “born again” became part of the nomenclature of American culture. Many people began to call themselves “born-again Christians”. That term, however, is a kind of stuttering, because “born-again Christian” is really a redundancy. It’s like speaking about “an unmarried bachelor” or “three-sided triangle.” All bachelors are unmarried and all triangles have three sides. The simple reality is this: everyone who is truly a Christian is born again. There’s no such thing as a non-born-again Christian or an unregenerate Christian. Yes, there are plenty of unregenerate church members and plenty of unregenerate people who profess to be Christians, but a person cannot be in Christ unless he or she is regenerate. By the same token, if you are regenerate, you are a Christian.
…there is an absolute requirement that must be met if a person is to enter God’s kingdom. A person must be changed by God; the disposition of his heart, which by nature does not want to do God’s bidding, must be altered by God the Holy Spirit. Man’s natural tendency is to flee from the presence of God and to have no affection for the biblical Christ. Therefore, if you have in your heart today any affection for Christ at all, it is because God the Holy Spirit in His sweetness, in His power, in His mercy, and in His grace has been to the cemetery of your soul and has raised you from the dead. So you are now alive to the things of Christ and you rejoice in the kingdom into which He has brought you.”
~ R.C. Sproul, John (St. Andrew’s Expositional Commentary)
“Truly, truly, I say to you, unless one is born again he cannot see the kingdom of God.” Nicodemus said to him, “How can a man be born when he is old? Can he enter a second time into his mother’s womb and be born?” Jesus answered, “Truly, truly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God. That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. Do not marvel that I said to you, ‘You must be born again.’ The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.” ~ John 3:3-8