The Jews recognized the Lord’s status as the seed of David according to the flesh. Many of them admitted that Jesus was a royal descendant of David (Matt. 1:1; 9:27; 12:23; 21:9, 15). However, regarding the Lord’s status as the Son of God, there was a great controversy among the Jews when He was on the earth (Mark 2:5-7; John 6:41-42). One day the Lord Jesus asked His disciples a question, “Who do men say that the Son of Man is?” (Matt. 16:13). They said, “Some, John the Baptist; and others, Elijah; and still others, Jeremiah or one of the prophets” (v. 14). This indicates that the Jews debated among themselves concerning His person. Without heavenly revelation they could realize, at most, only that He was the greatest among the prophets; none of them could know that He is the Son of the living God (v. 16). Eventually, the Jews condemned Him to death because He claimed that He was the Son of God (26:63-66; 27:43; Mark 14:61-64; Luke 22:70; John 5:18; 9:35-37). For the Jewish leaders, to declare oneself as the Son of God was blasphemy (10:30-33, 36). They thought that Christ was blaspheming God because they believed that He was not the Son of God but merely a man in the flesh.
Before His incarnation and resurrection, Christ was already the Son of God. After He became incarnate, however, His divine nature was concealed by the flesh. However, according to Romans 1:4, when He entered into resurrection, He was designated in power as the Son of God in His humanity. Unlike the resurrection of Lazarus (John 11:41-44) and of others (Luke 7:11-17; 8:49-54), the resurrection of Christ was not common but very particular. Christ’s resurrection is different because His resurrection was His designation as the Son of God.
There was no need for Christ to be designated as the Son of Man, because when people saw Him, they immediately recognized that He was a man. However, there was a need for Him to be designated the Son of God because the Son of God was concealed in Him as the Son of Man. His divinity was concealed in His humanity. People could easily recognize His humanity, but not His divinity. This concealed divinity needed to be designated, made manifest, by the resurrection. When He was resurrected, He was designated, or manifested, the Son of God with His humanity.
Before His incarnation, Christ, the divine One, already was the Son of God (John 1:18; Rom. 8:3). By incarnation He put on an element, the human flesh, which had nothing to do with divinity; that part of Him needed to be sanctified and uplifted by passing through death and resurrection. By resurrection His human nature was sanctified, uplifted, and transformed. Hence, by resurrection He was designated the Son of God with His humanity (Acts 13:33; Heb. 1:5). His resurrection was His designation. Now, as the Son of God, He possesses humanity as well as divinity. By incarnation He brought God into man; by resurrection He brought man into God, that is, He brought His humanity into the divine sonship. In this way the only begotten Son of God was made the firstborn Son of God, possessing both divinity and humanity. God is using such a Christ, the firstborn Son, who possesses both divinity and humanity, as the producer and as the prototype, the model, to produce His many sons (Rom. 8:29-30)—we who have believed in and received His Son. We too will be designated and revealed as the sons of God, as He was in the glory of His resurrection (vv. 19, 21), and with Him we will express God.
Christ as the seed of David according to the flesh was designated the Son of God according to the Spirit of holiness out of the resurrection of the dead. The Spirit of holiness in 1:4 is in contrast with the flesh in verse 3. Just as the flesh in verse 3 refers to the human essence of Christ, so the Spirit in verse 4 does not refer to the person of the Holy Spirit but to the spiritual essence of Christ’s divinity, that is, the divine essence of Christ. When Christ became a man and thereby put on humanity, He did not give up His divinity. He came to be a man in His divinity, and that divinity is the Spirit (John 4:24). While Christ was on the earth, He was both God and man. According to His humanity, He was the flesh. According to His divinity, He was the Spirit. Christ is therefore 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. Jesus’ divinity is the Spirit of holiness. This divinity, being the Spirit of holiness Himself, has the divine power and the divine element to transform Christ’s humanity, thereby making it divine.