What if one receives the Spirit of God when they are saved? Also, is God the one who searches the hearts?
I will answer more precisely soon. However for now the following answer is very related to your inquiry:
After Jesus' death on the cross and return to God, the Father, Paul had communion with Him. This was the point when Paul became saved, delivered, a child of God and a Christian. This was the final point of his passage.
Paul's approach before he came into communion with Jesus Christ and his experiences including his direct communion with Jesus Christ seem to be the passage which all humans must take and the experience which they must have in order to become saved, delivered, under grace of God, a child of God and a Christian. This has also been my own passage and experience which seems to have brought me into salvation, deliverance and made me a child of God and a Christian.
This event seemed to have been the natural follow through of Jesus' promise that when he left by dying the Spirit of Truth will come and deliver Truth which He did not or could not deliver when He was here physically. It seems that the Spirit of Truth was Jesus in Spirit form. Indeed it seems that Jesus in Spirit form is the Holy Spirit. Therefore it seems that Jesus' Spirit, the Spirit of Truth and the Holy Spirit is all the same.
Jesus was reportedly seen rising to heaven, in the air, in a physical body. The point is that Jesus did so, for showing those who did not know that one in Christ, could and does rise to heaven after death. However Jesus held this body, which had all reality of of being physical, only to a point, i.e. only until He had risen beyond human visibility.
It is not likely that Jesus (or anyone), could, would or did take His physical body to heaven. The fact is that things of earth is for earth and things of heaven are for heaven. The fabric of earthly things is different from the fabric of heavenly things and they need different sustenance for their upkeep.
Jesus' physical body was from earth. It was His mother's contribution and she was earthly, from earth. His mother provided the earthly element to create and sustain His physical body. Thereafter (i.e. after His birth) Jesus continue to support His physical body by eating and drinking in the normal human manner, essentially because His physical body was human. In heaven Jesus would not need a physical body nor would He (in heaven) have access to sustenance for a physical body. The fact is that when Jesus is in heaven with God, His Father, He is identical to God, His Father. God, His Father is Spirit, pure Spirit, and so too is Jesus, He too is Spirit.
God, Jesus' Father was and is from heaven and God. From this level and reality, God made a heavenly contribution to Jesus, the man on earth. God contributed Jesus' Spirit which was and remained the Holy Spirit, the Spirit of God, Himself. God who is a Spirit, the Holy Spirit, sent forth a part of Himself which is, it self, the Holy Spirit into a human physical body so that Jesus Christ, His son can be brought forth to earth. (remember we are told clearly, by Jesus himself, that God is Spirit)
However Jesus' mother contributed to Jesus, His human physical body. Therefore when Jesus was finished His God given mission as a man on earth, He left His physical body on earth and returned in Spirit to God, His Father who is Spirit.
Additionally, Jesus, the son of God, came from God who is in heaven. Jesus came from heaven (the realm of Spirit) and God, His Father, to be born on earth as a man. He did in order to walk on earth as a man and to experience death as man.
Then Jesus, the son of God, was done with His Father's mission, He went back to God, His father in heaven. Therefore in the middle Jesus was a man on earth. However before and after this Jesus was the fabric of God who is Spirit. He would not be different from God, His Father. When Jesus is with His Father He would be exactly like His Father. He would be Spirit like His Father.
We are told clearly that God is Spirit and we must recognized and worship God in Spirit. Can Jesus when He is absent from earth be any different? After Jesus' death from earth (i.e. when He returned to God, His Father in heaven), He could be no different from His Father. Jesus had to return to being Spirit. Therefore at that point and until now, Jesus, once again became and remains: Spirit, i.e. the Holy Spirit, just like God, His Father. And this is how Jesus took his place at the side of His Father.
My point being that this is how we are required to know Jesus Christ. We are required to know Jesus Christ in the same way as we would know and worship God, as Spirit. We would have to know Jesus as Spirit.
Therefore since Jesus is the Truth and the way and the light and no one comes onto God but through Jesus means that: one must know and go through Jesus, now in present time, to come onto God (i.e. to be saved, delivered, to become a child of God and a Christian).
And this is possible only by going through the Spirit of Jesus Christ, now in real time. And the fact is that: the Spirit of Jesus Christ is identical to the Spirit of God at this time. It is the Holy Spirit. And Paul confirmed clearly how one can have communion with the Holy Spirit which is to say, how how one can go though Jesus Christ or rather the Spirit of Jesus Christ, to come onto God.
Paul did confirm unequivocally: to search our heart to have communion with the Holy Spirit, that is to know precisely what the Holy Spirit has in mind for us and that the mind of the Holy Spirit is always in line with the will of God.
Since Jesus Spirit is the Holy Spirit, then this is how we go through Jesus Christ to come on to God. We go through the Spirit of Jesus Christ, which is the Holy Spirit the mind of who is discerned within our individual hearts.
The approach for becoming saved, delivered, a child of God and a Christian is no longer in mystery. It is no longer up in the sky. It is no longer a pie in the sky. The instruction is as clear as day. It is no longer unavailable. It was delivered by Jesus from His own experience of living on earth and dying violently. And it was tested and proven on Paul who expressed his experience in his revelations.
Indeed it is from Paul spirit to Spirit communion with Jesus Christ that he obtained the experience of become saved and delivered (i.e. on to Christ) and a child of God. Paul's experience of communion with Jesus in His Spirit is the path and the passage to salvation and deliverance and becoming a child of God and a Christian.
After experiencing direct and precise communion with the Jesus Christ after He died from earth and and returned to His Father to be Spirit like God, His Father, Paul delivered to those who can search their heart that:
each one must search one's own heart to discern precisely what the Holy Spirit has in mind for one. And that the mind of the mind of the Holy Spirit is always in line with the will of God. And it is by unconditionally obeying precisely what the Holy Spirit has in mind for us as discerned in this manner, that one is saved, delivered into heaven, becomes a child of God and a Christian.
This is an obvious follow up from a few verses before, that is, when Paul also confirmed that sons of God are led by the Spirit of God (i.e. Holy Spirit) And Jesus original statement that only those who do the will of God, His Father will be saved and delivered.
It seems therefore to become saved and delivered and a Christian and a child of God are all the same and this is accomplished by searching one's heart to discern precisely what the Holy Spirit spirit has in mind for one and obeying same unconditionally.
Also it seems that one must obey the mind of the Holy Spirit as discerned in this manner, unconditionally even if one must transgress all prevailing ideals and laws of society, morality and religiosity, including the Ten Commandments.
This seems to be the freedom, liberty and justification which are given to those in Christ.
And when one can live in this manner, that is when one is routinely always, unconditionally obedient to precisely what the Holy Spirit has in mind for one as discerned within one's heart or spirit in real time all the time, even of one has to transgress prevailing ideals and laws of society, morality and religiosity, one is also glorified by God.
This is the Gospel of un-circumcision which was rendered onto Paul. It is righteousness of God without laws.
To be come 'born again' is simply the actualization of one capacity to search one's heart.
To become 'born again' is to becomes aware of one's spirit or heart. This is the removal of 'the vial' over one's heart. This bringing one (divinely or otherwise) into awareness of one's heart or spirit or inward man.
Every one has a natural man (one's physical body) and one has an inward man (a spirit or heart) One is from earth and man, the other is from heaven and God. Both these bodies has faculties.
Our natural man or physical body has physical based (or earthly) faculties. These are our five physical senses and our capacity to think (which is done through our physical brain). When we dies we loose our physical body and we can no longer detect anything through our physical senses, not can we think.
Our inward man or spirit body has spirit based (or heavenly) faculties called intuitions. These were described by Jesus as, 'the eyes to see', 'the ear to hear' and 'the hearts to understand', Truth.
When we die we simply loose our physical body. Then we can no longer detect anything through our physical senses, nor can we think. However since we retain our inward man, we can know and detect the creation, Jesus and God through the intuitive faculties of our inward man or spirit.
To be 'born again' is simply to act of becoming aware of one's inward man and its intuitive faculties during our life on earth. It is described as our second birth. Our first birth is the be be born physically and physically aware. Our second birth is simply to become aware of our second side, our inward man. That is the removal of the 'vail' over (covering) 'our heart' which is also called our spirit or inward man.
Then one can search one's heart or spirit or inward man to know precisely what the Spirit of Jesus Christ has in mind for one. Jesus' Spirit is always in line with the will of God. Only with the removal of this 'vail' over one's heart (i.e. 'born again") that one can attempt to actually search one's heart. Before this one's heart is blocked and inaccessible. On cannot use this new approach.
Everything, including salvation and deliverance into heaven, hinges on being 'born again', that is, on the removal of that 'vail' over one's heart. Only then can one successfully search one's heart to know precisely what the Spirit of Jesus Christ (i.e. the Holy Spirit) has in mind for one. And the Spirit of Jesus Christ (i.e. the Holy Spirit) is always in line with the will of God. This is how humans know God.
Then by obeying precisely what Jesus' Spirit has in mind for us as discerned within our own heart, we will be doing the will of God, we will come onto God and we will enter God's kingdom of heaven.
This is how Jesus is the Truth, the way and the light and no one comes onto God but through Him. By going though His Spirit which is the Holy Spirit, from within our own heart or inward man, now in real time and all and every time thereafter, for ever and ever.