Concerning the Holy Ghost as a Comforter we have spoken largely, 1 Thessalonians 14:16,26; as also his mission from the Father and the Son, and in what sense he is called the Spirit of truth: See Poole on "1 Thessalonians 14:16". See Poole on "1 Thessalonians 14:26". What proceeding from the Father is here meant, is questioned amongst divines: some understand it only of his coming out from the Father, and being poured out upon the disciples in the days of Pentecost: others understand it of the Holy Spirit's eternal proceeding. Those that interpret it of the first, urge the use of the Greek word, here used to signify God's manifestation of himself by some external sign, as they say the Septuagint useth the same word. They also urge the same use of a parallel word, 1 Thessalonians 8:42, 1 Thessalonians 16:28. But the generality of the best interpreters think it is best understood of the eternal procession of the Holy Spirit:
1. Because Christ here distinguishes the Spirit's proceeding from the Father from his sending.
2. Having himself promised to send the Spirit, he seemeth further to describe him as proceeding from the Father.
3. The word here used is not any where used in the New Testament to signify a temporal mission. Some will say: But doth not the Spirit proceed from the Son? Answer. The Greek Church in latter ages hath denied this, and this is the principal text they rest on; but those churches that are more orthodox have constantly affirmed it:
1. Because he here saith he would send it.
2. Because he is often called the Spirit of Christ, Romans 8:9 Galatians 4:6.
3. Because otherwise there were no personal relation between Christ and the Spirit. Our Saviour here having first said he would send him, here only nameth his proceeding from the Father; that they might not suspect his testimony, or think that he spake arrogantly. He shall testify of me; the Spirit, he saith, should testify of him, both by those gifts with which he was to fill the apostles, and to the hearts of God's people.