“Jesus answered and said to him, ‘Most assuredly, 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, “Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God.'”John 3:3-5
Initially that sounds contradictory, but that depends on whether your understanding of holiness is from God’s perspective or mans. To step from an immediate experience of placing yourself under the saving blood of Jesus Christ, acquires immediate holiness before God, or your understanding of determining to put off everything that is indicative of your old life and growing in the grace of Christ. — Putting off old patterns of living, or putting on attire that is more in keeping with the lifestyle of our Savior.
A child is brought into this world; they are born. Naturally they continue to grow and eventually become adults. That process involves defining moments day by day as, hopefully, positive changes indicate maturity into the man or woman that you expect them to be. So it is with the child of God, that one who was born again by the Spirit of God as they beckoned the Savior to be their Savior. (John 3:3-5)
Just to emphasize a point—One relates to our standing before the Lord while the other refers more to the growing process where sanctifying, though positional, is also more likeness to our Savior. Peter draws an excellent work of the entire process in the opening verses of his first epistle. Even after listing all the saints “scattered”, he reminds them, and us, “who are chosen according to the foreknowledge of God the Father, by the sanctifying work of the Spirit, to obey Jesus Christ and be sprinkled with His blood: May grace and peace be yours in the fullest measure.”
To acquire positional holiness accept Christ! To acquire practical holiness obey Christ!