Life and building are two great matters in the Bible.
Life is God Himself. This is not the created life that all creatures have. But here I mean the uncreated and divine life of God.
And building refers to God working this divine life into human life so that man becomes a corporate expression of the mingling of divinity and humanity.
John 14 is a good place to see these two matters.
"In My Father's house are many abodes; if it were not so, I would have told you; for I go to prepare a place for you." (John 14:2)
Here we see the building of God mentioned, "My Father's house." And we also see the divine life of God in Christ:
"Thomas said to Him, Lord, we do not know where You are going; how can we know the way? Jesus said to him, I am the way and the reality and the life; no one comes to the Father except through Me." (vv. 5,6)
And here we see life mentioned. Christ is the divine life. Life and building are here in John 14.
According to the interpretation of John 2:16,21 "My Father's house" refers to the temple, the body of Christ, as God's dwelling place.
Jesus refered to Himself as the antitype and reality of the temple of God in Jerusalem:
"Jesus answered and said to them, Destroy this temple, and in thrtee days I will raise it up. Then the Jews said, This temple was built in forty-six years, and You will raise it up in three days?
But He spoke of the temple of His body. When therefore He was raised from the dead, His disciples remembered that He had said this, and they believed the Scripture and the word which Jesus had spoken." (John 2:19-22)
At that time when Jesus said that if they destroyed the temple of God He [Jesus] would raise it up in three days, the temple of God was only His individual body. But through death and resurrection, the body of Christ has increased to be His mystical corporate Body. This is the church with all the believers in Jesus, who have been regenerated through Christ's resurrection:
First Peter 1:3 shows His resurrection is the source of their being regenerated:
"Blessed be the God and Father of our Lord Jesus Christ, who according to His great mercy has regenerated us unto a living hope through the resurrection of Jesus Christ from the dead."
In Christ's resurrection the church is the body of Christ, which is the house of God (1 Tim. 3:15; 1 Pet. 2:5; Heb. 3:6), God's habitation (Eph. 2:21-22), God's temple (1 Cor. 3:16-17).
"In my Father's house are many abodes ..." (14:2a)
The "many abodes" are tje many members of the Body of Christ (Rom. 12:5), which is God's temple (1 Cor. 3:16-17). This is proven by the fact that the singular of the same Greek word is used in verse 14 when Jesus says that He and His Father, as the divine "We" will come to the lover of Jesus and make an abode with him.
To make an abode with them is to come to them as divine life. And to build them into the Father's house is to saturatee them, fill them, permeate them, soak them in the divine life.
Regeneration (being born again), then is for the building of the Father's house the corporate living temple where God is mingled into man.
"In My Father's house are many abodes; if it were not so, I would have told you; for I go to prepare a place for you.
And if I go and prepare a place for you, I am coming again and will receive you to Myself, so that where I am you also may be." (vv.2,3)
Where is He? He is mingled with God. He is totally united with God as to be one organic incorporation of divinity and humanity. His salvation is to bring man to where He is. And His prayer to His Father was that His people would be with Him where He is - in the Father and the Father in Him:
"Father,concerning that which You have given Me, I desire that they also may be with Me where I am, that they may behold My glory, which You have given Me, for You loved Me before the foundation of the world." (John 17:24)