The day of Pentecost that fully came with the record quoted above had been in the process of coming ever since Genesis 3:15 when God had made the promise to man of the coming seed - the Christ who was to redeem mankind.

 Pentecost  was the celebration of the feast of  firstfruits of wheat harvest.  It was a time to celebrate new beginnings.  New life.  For the twelve apostles that day, and for believers since that day, it was a new beginning.  It was the first time anyone was  born again .  It was the first time anyone  spoke in tongues .  It was the first time  God's purpose for man was a reality.

God originally designed man to be body, soul, and spirit ; a three part being.  In Genesis Chapters 1-2 mankind had a physical body, soul life, and spirit life.  Two "life forms" were part of man's nature.  When one loses life one dies.  Adam lost his spirit life when he disobeyed God.  He still had soul life which made him a living, moving being that could think and act.  But spiritually he was dead and mankind was left without a connection to God.

What makes mankind different from the other life (animals, fish, etc.) on the earth?  Without spirit - not much!  Animals have soul life just as man does.  But God designed man to have spirit life as well.  He made the mind of man to hold and believe His word.  He designed man to communicate with Him. Man lost his spirit life, but the system was still designed to have it.  When you buy a house or rent an apartment that is cable ready, all you need is a receiver such as a VCR & television set or cable box & television set in order to watch cable TV.  God designed mankind cable ready. We were meant to have spirit within and our minds were designed to operate the spirit of God and communicate with Him.  However, due to the disobedience of Adam we lost our receiver.  From that time on mankind waited for a redeemer who would come and walk perfectly before God so that mankind could once again be body, soul, and spirit - a three part being with a direct connection to God.

That which came on the day of Pentecost was even greater than that which was originally a part of man.  The spirit given on the day Pentecost is born within man when he believes Romans 10:9-10 and is called in the Bible seed.  It is no longer conditional.  It is a permanent part of man that cannot be lost once born within.

I Peter 1:18-23
     Forasmuch as ye know that ye were not redeemed with corruptible things, as silver and gold, from your vain conversation [empty way of life] received by tradition from your fathers;
     But with the precious blood of Christ, as a lamb without blemish and without spot:
     Who verily was foreordained before the foundation of the world, but was manifest in these last times for you.
    Who by him do believe in God, that raised him up from the dead, and gave him glory: that your faith [believing] and hope might be in God.
     Seeing ye have purified your souls in obeying the truth though the Spirit [not in the text] unto unfeigned love of the brethren, see that ye love one another with a pure heart fervently:
     Being born again, not of corruptible seed, but of incorruptible, by the word of God, which liveth and abideth for ever.

When we confess with our mouth the Lord Jesus Christ and believe in our heart that God raised him from the dead, God creates holy spirit within us.  We are literally born again.  The first time we were born we were born by natural birth with body and soul life only.  When we accept Jesus Christ as Lord and believe God raised him from the dead we are born a second time - with spirit life.  We are now, as God originally intended, three part beings.  Only, this time spirit life is born in man.  It is seed. And it is incorruptible.  It cannot die.  What a birthday!  Pentecost is a new birthday for believers.

Nicodemus, a ruler of the Jews - a Pharisee, asked Jesus about the things of God and Jesus reminded him of that which he should have known as a doctor of the Old Testament: that holy spirit was going to be restored to mankind and that man had to be born again - having spirit within - if man was to understand God.

John 3:3-7
     Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again [gennao anothen], he cannot see the kingdom of God.
     Nicodemus saith unto him, How can a man be born when he is old?  can he enter the second time into his mother's womb, and be born?
     Jesus answered, Verily, verily, I say unto thee, Except a man be born of water [the natural first birth - body & soul] and of the Spirit, he cannot enter into the kingdom of God.
     That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
     Marvel not that I said unto thee, Ye must be born again [gennao anothen].
 

The Greek words for born again are gennao anothen which literally means born from above.  Nicodemus should have known about man's need for spirit and the promise of God.  But he just could not understand it.  Jesus could not understand how a believer, schooled in the Old Testament, could be so unaware of the promise of God and that which the Christ was to make available once again.

John 3:9-10
     Nicodemus answered and said unto him, How can these things be?
     Jesus answered and said unto him, Art thou a master of Israel, and knowest not these things?

When we are born again, God creates spirit life in us.  We are born from above.  We are born from God.  God is our father and we are his children.

I John 3:1-2a
     Behold what manner of love the Father hath bestowed upon us, that we should be called the sons of God:  therefore the world knoweth us not, because it knew him not.
     Beloved, now are we the sons of God, . . .

Having sons with a spiritual connection with their Father was God's purpose from the beginning.  It was His grand design. It is what He purposed in Himself and wanted for mankind.

Ephesians 1:4-5
     According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love:
     Having predestinated us unto the adoption of children [placing as sons] by Jesus Christ to himself, according to the good pleasure of his will.

As we have already seen God placed His seed within us - spirit life.  That is birth.  It is not adoption as we think of adoption.  The words adoption of children used here and in Romans 8:15 mean to be placed as a son.  God made us His sons by placing holy spirit within us when we believed.  We were literally born of God.  This was the good pleasure of His will!  It is what God wanted and planned for in the beginning but did not see come to pass until Pentecost.

Romans 8:15-17a
     For ye have not received the spirit of bondage again to fear; but ye have received the Spirit of adoption [sonship spirit - to be placed as a son], whereby we cry, Abba [an endearing term like daddy], Father.
     The Spirit itself beareth witness with our spirit, that we are the children of God:
     And if children, then heirs, heirs of God, and joint-heirs with Christ; . . .

Not only did God plan to have children, God planned to have heirs.  The day of Pentecost was a birthday for us that guarantees us an inheritance.  That is what God wants for us!

Ephesians 1:11
     In whom we also have obtained an inheritance, being predestinated according to the purpose of him who worketh all things after the counsel of his own will:

God planed for man to be a three part being.  God predestinated an inheritance for man.  God predestinated sonship for man.  God wanted children who would love Him and communicate with Him as their Father.  Thanks to the accomplished work of the Lord Jesus Christ God's purpose has been fulfilled.   Now all we have to do is believe and receive it.  Happy New Birthday Believers.  We are the sons of God!