Romans 1:4 says that Christ’s humanity “was designated the Son of God in power according to the Spirit of holiness out of the resurrection of the dead.” Here the Spirit of holiness is different from the Holy Spirit. In the Divine Trinity there are three Persons, and the third One is the Holy Spirit, but the Spirit in Romans 1:4 is the same as that mentioned in John 4:24, where the Lord Jesus said, “God is Spirit.” This does not mean that God is the Holy Spirit. To say that God is the Holy Spirit is right, but John 4:24 does not refer to the Holy Spirit of the Divine Trinity. It refers to the Spirit as God’s essence, God’s nature. To say that God is Spirit is like saying that a stand made of steel is steel. Steel is the very essence of the stand. In the same way, Spirit is the essence of God. When Christ became a man, picking up humanity, He did not give up His divinity. He came to be a man in His divinity, and that divinity is the Spirit, as mentioned in Romans 1:4 and John 4:24.
Christ, while He was on the earth, was both God and man. According to His being a man, He was the flesh. According to His being God, He was the Spirit. Christ is one person of two natures, the divine nature and the human nature. The human nature is the flesh, and the divine nature is the Spirit.
First Peter 3:18 says that when Christ was being put to death on the cross, His flesh was being put to death, not His Spirit. His Spirit, at the same time, was very active, was made alive. One person was crucified on the cross. According to His flesh, He was crucified, but according to His Spirit, He was very active, made strong.
According to the Spirit of holiness, Christ was designated the Son of God. According to the flesh, He was the Son of David. But according to the Spirit, He was the Son of God. According to His humanity, He was the Son of Man, but how could His humanity become the Son of God? This is one of the hardest points in the Bible for us to understand.
We are human beings, so we are all sons of man. How can God make us His children? God does this by regeneration. Human beings are the sons of man. God’s children are the children of God. We human beings have been made children of God by regeneration. Regeneration is God coming into us, into our spirit, to be an element added into our human spirit. In regeneration our human spirit was made divine. When we were regenerated by God, we were made divine.
In the same principle, while Christ was on this earth before His resurrection, a part of Him, His humanity, was not divine. That human part was the Son of Man, not the Son of God. In His death His human part was crucified. Then in His resurrection God the Spirit as Christ’s divinity was made strong, very active, to put divinity into the humanity of Christ to make it divine. This is the same principle of our regeneration. Before Christ’s resurrection, Christ’s humanity was just human. But in Christ’s resurrection, His divinity as the Spirit was made strong to impart Himself into His humanity to make it divine. Thus, Christ became the Son of God in His humanity.
The Son of God in resurrection is different from the only begotten Son of God. The only begotten Son of God was only divine, without humanity. But the Son of God in resurrection is both divine and human, so this Son of God is not the Only Begotten but the Firstborn among many brothers (Rom. 8:29). Thus, we may say that Christ in His humanity was the first one regenerated, so He became our firstborn Brother, and we became His many brothers. He and we all were regenerated in His resurrection.
Ephesians 2 reveals that in our spirit we were dead in offenses, but when Christ in His resurrection was made alive, we were made alive together with Him (v. 5). His humanity was crucified, but in resurrection His humanity was made alive by the Spirit. Ephesians 2 says we were made alive and resurrected with Christ (vv. 5-6). This confirms Romans 1. We were regenerated by being made alive with Christ, by being raised up with Christ. First Peter 1:3 tells us that in the resurrection of Christ, God has regenerated all the believers.
Power in Romans 1:4 is the power of life. The phrase inpower corresponds with 1 Peter 3:18, which says that Christ’s flesh was put to death, but His Spirit was made alive. To be made alive means to be empowered.
Christ came to be a man. He came out of the seed of David, so the seed of David is the source of Christ’s flesh. Then Christ’s humanity through resurrection became the Son of God out of resurrection. As the Son of Man, He came out of the seed of David. As the Son of God, He came out of resurrection. The resurrection is the Triune God embodied in Christ. In John 11:25 the Lord Jesus, the embodiment of the Triune God, said, “I am the resurrection.” That means the Triune God is the resurrection. If there were no God, there would be no resurrection in this universe. Resurrection is God, and this is the source out of which the firstborn Son of God came into being.