The actual term "born again" which is what Nicodemus was supposed to have understood comes from Ezekiel.
Eze 36:25 Then will I sprinkle clean water upon you, and ye shall be clean: from all your filthiness, and from all your idols, will I cleanse you.
Eze 36:26 A new heart also will I give you, and a new spirit will I put within you: and I will take away the stony heart out of your flesh, and I will give you an heart of flesh.
Eze 36:27 And I will put my spirit within you, and cause you to walk in my statutes, and ye shall keep my judgments, and do them.
This was for the faithful remnant of Israel that would enter the earthly kingdom. While Christians could be called "regenerated" when receiving new and eternal life when placed into the body of Christ, it can be confusing to also call this being "born again".
Hey Tim
That's what born again is. When we are placed in Christ, we become spiritually one with Him. At that same placing into Him, we are also, in effect, placed into His death and resurrection, meaning we die with Him and are raised up with Him. This is born again. I'm, going to start a thread on that very topic.
I agree that the promise was made go all the way back in Ezekiel. The promise, The Holy Spirit indwelling, called the baptism with the Holy Spirit, resulting in being born again, was still future. We can see this same future promise still not fulfilled in John 7:38-39.
John 7:38-39 He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water." But this He spoke concerning the Spirit, whom those believing in Him would receive; for the Holy Spirit was not yet given, because Jesus was not yet glorified.
Compare that to EZ. 36:25-27. Also, vs. 27, should be capitol "S", as in Spirit, not spirit. The NKJV fixed that and use a capitol "S" when the Bible is speaking of the Holy Spirit, and a small "s" when speaking of our spirit.
Anyways, this was exactly Jesus' point in John 3. After explaining born again, Jesus says this in 3:14-15.... In other words, this must happen first....
John 3:14-15 No one has ascended to heaven but He who came down from heaven, that is, the Son of Man who is in heaven. And as Moses lifted up the serpent in the wilderness, even so must the Son of Man be lifted up, that whoever believes in Him should not perish but have eternal life.
This all points to Pentecost and the baptism (placing into Christ) with the Holy Spirit [indwelling]. The reason Nicodemus didn't understand Jesus was because He was not born again. Nobody can be born again unless they are in Christ. Nobody can be placed in Christ without the Holy Spirit indwelling that places us in Christ. That indwelling was not available until Pentecost.
Here are some more verses to consider. John 12:32-33, 14:25-29, 15:26, 16:7, -->16:12-16 <-- This is why Nicodemus didn't understand.
Prophesied, Jesus is the baptizer, the Holy Spirit is the Agent of that baptism.