In Western society I think we may have trouble with certain concepts which are relevant to Christianity. It seems as if in western civilization our thinking is more carnal (fleshly) than in the eastern culture. I think it is important to remember the birth of Christianity was in the Middle EAST. We also should remember the “scientists” of the days of Paul were more philosopher than scientist. The culture which bred the Apostles was steeped in Greek philosophy. Especially the case of Paul who had received an exemplary education before conversion. Added to the fact the eastern mind set is of a more “spiritual” nature as opposed to those of the west who seem to be more “physical” I feel that some spiritual concepts are hard to be fully comprehended by those of us in the West.
One of these concepts is Oneness or being in Him and Him in us. Now the eastern teaching is one of “being one with the universe” But we as Christians are to be one with each other and one with the Lord. My understanding of the concept from the east is:
Oneness with the universe: being at peace with the realization there is a bigger universe of which we are only a part. The awareness of your place in the scope of the universe. The realization we are inter-related with a bigger universe and no relationship is meaningless.
The relevance of this is to make real to us Christians the concept we are indeed nothing outside of the Lord and everything in Him. Sometimes I think we sometimes get so self-righteous we forget the truth we are NOTHING without Jesus. Let me share some verses with you about being “in Christ”. If we learn nothing else, if we just get a glimmer of all it entails the reality of eternal security becomes self evident.

Gal.3:[26] For ye are all the children of God by faith in Christ Jesus.
[27] For as many of you as have been baptized into Christ have put on Christ.
[28] There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus.
[29] And if ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise.

When I was born I was born “in Adam” and in Adam I will die a physical death and I died spiritually the moment I knowingly committed sin (1 Corinthians 15:22) but in Christ I am born again on the inside and made alive through Jesus Christ and given the hope of eternal life. I am now in Him and He in me.

Col.2:[1] For I would that ye knew what great conflict I have for you, and for them at Laodicea, and for as many as have not seen my face in the flesh;
[2] That their hearts might be comforted, being knit together in love, and unto all riches of the full assurance of understanding, to the acknowledgement of the mystery of God, and of the Father, and of Christ;
[3] In whom are hid all the treasures of wisdom and knowledge.
[4] And this I say, lest any man should beguile you with enticing words.
[5] For though I be absent in the flesh, yet am I with you in the spirit, joying and beholding your order, and the stedfastness of your faith in Christ.
[6] As ye have therefore received Christ Jesus the Lord, so walk ye in him:
[7] Rooted and built up in him, and stablished in the faith, as ye have been taught, abounding therein with thanksgiving.
[8] Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ.
[9] For in him dwelleth all the fulness of the Godhead bodily.
[10] And ye are complete in him, which is the head of all principality and power:
[11] In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ:
[12] Buried with him in baptism, wherein also ye are risen with him through the faith of the operation of God, who hath raised him from the dead.
[13] And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses;

In Christ we have all that we need. He experienced death for us, He experienced Hell for us, He has been resurrected for us and He now sits in Heaven . We have been spiritually circumcised through faith. An internal operation which occurred the moment we put our trust in Jesus Christ. Though physically on earth we are spiritually in Heaven. We are here on earth for a time so we may walk in Him and show a lost and dying world the love of God and make manifest His will to those who are without.

2Cor.5:[14] For the love of Christ constraineth us; because we thus judge, that if one died for all, then were all dead:
[15] And that he died for all, that they which live should not henceforth live unto themselves, but unto him which died for them, and rose again.
[16] Wherefore henceforth know we no man after the flesh: yea, though we have known Christ after the flesh, yet now henceforth know we him no more.
[17] Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new.
[18] And all things are of God, who hath reconciled us to himself by Jesus Christ, and hath given to us the ministry of reconciliation;
[19] To wit, that God was in Christ, reconciling the world unto himself, not imputing their trespasses unto them; and hath committed unto us the word of reconciliation.
[20] Now then we are ambassadors for Christ, as though God did beseech you by us: we pray you in Christ’s stead, be ye reconciled to God.
[21] For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.

We become born again. We are no longer ourselves but Christ in us and through us. Everything is new for us. New hope, new destination, new purpose, new motive etc. We are an ambassador of our new home. Presenting the gospel and living the gospel in a foreign land. We are no longer ourselves but Jesus to the lost world. Showing the love of God in our attitude and dealings with those around us.

Romans 8:[38] For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come,
[39] Nor height, nor depth, nor any other creature, shall be able to separate us from the love of God, which is in Christ Jesus our Lord.

Nothing can separate us from the love of God when we become in Him.

1 Corinthians 1:2 Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called to be saints, with all that in every place call upon the name of Jesus Christ our Lord, both theirs and ours:

In Him I am sanctified and made a saint.

11 Corinthians 1:19 For the Son of God, Jesus Christ, who was preached among you by us, even by me and Silvanus and Timotheus, was not yea and nay, but in him was yea.
[20] For all the promises of God in him are yea, and in him Amen, unto the glory of God by us.
[21] Now he which stablisheth us with you in Christ, and hath anointed us, is God;
[22] Who hath also sealed us, and given the earnest of the Spirit in our hearts.

I now receive all of the promises of God and am established by God in Christ.

Ephesians 1:3 Blessed be the God and Father of our Lord Jesus Christ, who hath blessed us with all spiritual blessings in heavenly places in Christ:

In Him I have every spiritual blessing in Heaven.

Ephesians 1:4 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:

In Him I am now GUARANTEED to be presented before God PERFECT.

Ephesians 1:6 To the praise of the glory of his grace, wherein he hath made us accepted in the beloved.

In Him I am promised to be accepted by God.

Ephesians 2:5 Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;)
[6] And hath raised us up together, and made us sit together in heavenly places in Christ Jesus:

In Him I am already sitting in Heaven.

Ephesians 2:13 But now in Christ Jesus ye who sometimes were far off are made nigh by the blood of Christ.

In Him I am now near to God.

Ephesians 2:21 In whom all the building fitly framed together groweth unto an holy temple in the Lord:
[22] In whom ye also are builded together for an habitation of God through the Spirit.

In Him I grow and am a temple for the Holy Spirit.

Ephesians 5:8 For ye were sometimes darkness, but now are ye light in the Lord: walk as children of light:

I am no longer darkness I am now light to the lost.