Oneness

Not Identicality

 * See also Trinity

Oneness refers to a sharing of spirit, because a spirit can inhabit multiple bodies (e.g. the Holy Spirit). It does not mean different individuals are the same, which should be evident from John 17:11,20-22; since Jesus says Christians are one with God the Father and Him in the same way He and God the Father are with each other. Christians are no more identical to God the Father and Jesus than they are to one another. God the Father, Jesus the Son of God, and the Holy Spirit are all individuals, but God the Father is greater in power, authority, and knowledge. (John 14:28; Mark 13:32; 1 Corinthians 15:28)

John 17:11 And now I am no more in the world, but these are in the world, and I come to thee. Holy Father, keep through thine own name those whom thou hast given me, that they may be one, as we are.

John 17:20 Neither pray I for these alone, but for them also which shall believe on me through their word; 21 That they all may be one; as thou, Father, art in me, and I in thee, that they also may be one in us: that the world may believe that thou hast sent me. 22 And the glory which thou gavest me I have given them; that they may be one, even as we are one: 23 I in them, and thou in me, that they may be made perfect in one; and that the world may know that thou hast sent me, and hast loved them, as thou hast loved me.

John 14:28 ¶ Ye have heard how I said unto you, I go away, and come again unto you. If ye loved me, ye would rejoice, because I said, I go unto the Father: for my Father is greater than I.

Mark 13:32 But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father.

1 Corinthians 15:28 And when all things shall be subdued unto him, then shall the Son also himself be subject unto him that put all things under him, that God may be all in all.

A Sharing of Spirit
This is how oneness works: God pours out His spirit on "all flesh" as foretold, so that they are all one with each other. That is how Christians become one body of Christ, through having the spirits of God the Father, the Holy Spirit, and Jesus inside of them. By having the same spirit all Christians are made to spiritually be seated in heavenly places together and share a spiritual bond of fellowship. (Eph. 2:5-6)

Joel 2:28 ¶ And it shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions: 29 And also upon the servants and upon the handmaids in those days will I pour out my spirit.

John 14:23 Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him.

Acts 2:2 And suddenly there came a sound from heaven as of a rushing mighty wind, and it filled all the house where they were sitting. 3 And there appeared unto them cloven tongues like as of fire, and it sat upon each of them. 4 And they were all filled with the Holy Ghost, and began to speak with other tongues, as the Spirit gave them utterance.

1 Corinthians 12:4 Now there are diversities of gifts, but the same Spirit.

1 John 4:12 No man hath seen God at any time. If we love one another, God dwelleth in us, and his love is perfected in us. 13 Hereby know we that we dwell in him, and he in us, because he hath given us of his Spirit.

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:

Holy Spirit is an Person
The Holy Spirit is an individual not a force. The Bible says the Holy Spirit can be grieved and is our access to God the Father.

Ephesians 4:30 And grieve not the holy Spirit of God, whereby ye are sealed unto the day of redemption.

1 Corinthians 12:13 For by one Spirit are we all baptized into one body, whether we be Jews or Gentiles, whether we be bond or free; and have been all made to drink into one Spirit.

Ephesians 2:18 For through him we both have access by one Spirit unto the Father.

Galatians 3:28 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.

Hebrews 2:11 For both he that sanctifieth and they who are sanctified are all of one: for which cause he is not ashamed to call them brethren,

John 14:23 Jesus answered and said unto him, If a man love me, he will keep my words: and my Father will love him, and we will come unto him, and make our abode with him.

Now, Jesus, God the Father, and God the Holy Spirit all are said to bear witness in Heaven.

1 John 5:6 This is he that came by water and blood, even Jesus Christ; not by water only, but by water and blood. And it is the Spirit that beareth witness, because the Spirit is truth. 7 For there are three that bear record in heaven, the Father, the Word, and the Holy Ghost: and these three are one. 8 And there are three that bear witness in earth, the Spirit, and the water, and the blood: and these three agree in one.

However, there does seem to be a progression in authority. Jesus is above all but God the Father, since Jesus helped create all that exists. Jesus is above humans and every other name. God the Father is the only one above Jesus.

Ephesians 1:21 Far above all principality, and power, and might, and dominion, and every name that is named, not only in this world, but also in that which is to come: 22 And hath put all things under his feet, and gave him to be the head over all things to the church, 23 Which is his body, the fulness of him that filleth all in all.

Colossians 1:15 Who is the image of the invisible God, the firstborn of every creature: 16 For by him were all things created, that are in heaven, and that are in earth, visible and invisible, whether they be thrones, or dominions, or principalities, or powers: all things were created by him, and for him: 17 And he is before all things, and by him all things consist. 18 And he is the head of the body, the church: who is the beginning, the firstborn from the dead; that in all things he might have the preeminence. 19 For it pleased the Father that in him should all fulness dwell;

John 14:28 Ye have heard how I said unto you, I go away, and come again unto you. If ye loved me, ye would rejoice, because I said, I go unto the Father: for my Father is greater than I.

John 8:17 It is also written in your law, that the testimony of two men is true. 18 I am one that bear witness of myself, and the Father that sent me beareth witness of me.

Oneness even applies to marriage as well it seems:

Mark 10:7 For this cause shall a man leave his father and mother, and cleave to his wife; 8 And they twain shall be one flesh: so then they are no more twain, but one flesh.

1 Corinthians 6:16 What? know ye not that he which is joined to an harlot is one body? for two, saith he, shall be one flesh. 17 But he that is joined unto the Lord is one spirit.

It is interesting that the book of Acts as well as other books repeatedly speaks of the Christian church worshipping God with a oneness or singleness of heart, mind, and spirit. (Acts 1:14, 2:1, 2:46, 4:24, 4:32, 5:12,15:25, Romans 12:16, 15:5-7, 1 Corinthians 3:8, 2 Corinthians 13:11, Philippians 1:27, 2:2, 1 Peter 3:8)

Paul uses the analogy of the Christian body to describe how Christians are one as a church, with different members but one whole. (Romans 12:4-8, 1 Corinthians 10:17, 12:4-31, Colossians 3:15)

There's a lot of confusion over what the Bible means when it speaks of oneness, hopefully this helps clarify somewhat.