THE SPIRIT OF JESUS CHRIST
Philippians 1:19 says, "For I know that for me this will turn out to salvation through your petition and the bountiful supply of the Spirit of Jesus Christ." Here it is not just the Spirit of Jesus but the Spirit of Jesus Christ. The Greek word for bountiful supply is a special word used by the Greeks when they referred to the supplying of all the needs of the chorus by the choragus, the leader of the chorus. In ancient times, according to the Greek custom, the leader, the choragus, of the chorus had to prepare and supply everything that the chorus needed. Now the apostle Paul used the same word to describe the bountiful supply of the Spirit of Jesus Christ.
THE SPIRIT OF CHRIST
Romans 8:9 says, "But you are not in the flesh, but in the spirit, if indeed the Spirit of God dwells in you. Yet if anyone does not have the Spirit of Christ, he is not of Him." This verse interchangeably uses the Spirit of God and the Spirit of Christ. The Spirit of Christ is the Spirit of God. They are one Spirit.
THE SPIRIT OF GOD IN THE OLD TESTAMENT
AND THE SPIRIT IN THE NEW TESTAMENT
If we want to know what the Spirit is, we first have to distinguish the Spirit of God in the Old Testament from the Spirit in the New Testament. In the fifth chapter of his book The Spirit of Christ, Andrew Murray told us that in the whole Old Testament there is not such a title as the Holy Spirit. In the entire Old Testament you cannot find the title the Holy Spirit ascribed to the Spirit of God. (In Psalm 51:11 and Isaiah 63:10-11, Holy Spirit should be translated Spirit of holiness.)
The title the Holy Spirit was used first in connection with the preparation for the Lord’s coming through incarnation (Luke 1:15, 35). It was at that time that the holy Scripture used the term the Holy Spirit for the Spirit of God. Hence, this title the Holy Spirit is related to the fact that God mingled Himself with man through incarnation. Such a mingling cannot be found in the Old Testament.
The Old Testament mentions a number of times that the Spirit of God, or the Spirit of Jehovah, came down upon the prophets or upon a certain person (Judg. 3:10; 6:34; 11:29; 13:25; 14:6, 19; 15:14; 1 Sam. 10:6; 16:13-14; 2 Sam. 23:2; 1 Kings 18:12; 22:24; 2 Kings 2:16; 2 Chron. 18:23; 20:14; Isa. 11:2; 63:14; Ezek. 11:5; 37:1; Micah 3:8; Zech. 7:12). Thus, in the Old Testament there was God, and there was the Spirit of God who came down upon people. At that time the Spirit of God had merely the element of divinity.
We know that God passed through a wonderful process in the New Testament. He became a man in incarnation, and His divinity was mingled with humanity. Then He passed through human living, crucifixion, and resurrection. In resurrection He was glorified and became the life-giving Spirit (1 Cor. 15:45b). This Spirit is all-inclusive. How many items are in this Spirit? The Son is in this Spirit, the Father is in this Spirit, and, of course, the Spirit is in this Spirit. The man whom Christ became through incarnation is in this Spirit. His human living, the effectiveness of His death, His resurrection, glorification, ascension, enthronement, kingdom, and authority are all included in this Spirit. Such a Spirit is the Spirit of Jesus (Acts 16:7), the Spirit of Christ (Rom. 8:9), and the Spirit of Jesus Christ (Phil. 1:19). In the Old Testament, the Spirit of God had merely the element of divinity. But today all the elements of God, man, human living, death, resurrection, glorification, ascension, enthronement, and the kingdom with the authority are in the Spirit. We have the bountiful supply of the Spirit of Jesus Christ.
(The Life and Way for the Practice of the Church Life, Chapter 6, by Witness Lee)