Here is another explanation by the WTS prior to the Trinity Brochure that Jonathan references above.....
*** w04 5/15 pp. 29-30 Questions From Readers ***
Questions From Readers
• How can we grieve God’s holy spirit, since it is not a person?
It was the apostle Paul who wrote: “Do not be grieving God’s holy spirit.” (Ephesians 4:30) Some take these words to be an indication that the holy spirit is a person. However, publications of “the faithful steward” have often provided Scriptural and historical proof that the early Christians viewed the holy spirit neither as a person nor as a god equal to the Most High as part of a so-called Trinity. (Luke 12:42) So Paul was not referring to God’s holy spirit as a person.
God’s holy spirit is his invisible active force. (Genesis 1:2) Jesus was to baptize “with holy spirit,” just as John was baptizing with water. (Luke 3:16) At Pentecost 33 C.E., some 120 disciples were “filled with holy spirit”—obviously not with a person. (Acts 1:5, 8; 2:4, 33) Such anointed ones received a heavenly hope, and God’s spirit led them in a life of faithfulness. (Romans 8:14-17; 2 Corinthians 1:22) The spirit produced godly fruitage and helped them to avoid the sinful “works of the flesh” that could result in divine disapproval.—Galatians 5:19-25.
If we are God’s servants with an earthly hope, we have not been anointed with holy spirit. Nevertheless, we can have just as much of God’s spirit as those with the heavenly hope. Hence, we too could grieve the spirit. But how?
If we were to ignore Scriptural counsel penned under the guidance of holy spirit, we could develop traits that could result in willful sin against the spirit, the loss of Jehovah’s favor, and eventual destruction. (Matthew 12:31, 32) We might not yet be sinning gravely, but we could be starting off on the wrong road, one that could eventually take us in a direction contrary to the leading of the spirit. Under such circumstances, we would be grieving the holy spirit.
How, then, can we avoid grieving God’s spirit? We certainly have to control our thoughts and actions. In his letter to the Ephesians, chapter 4, the apostle Paul spoke about avoiding tendencies toward dishonest statements, sustained wrathfulness, laziness, and unsuitable speech. If we have put on “the new personality” and yet allow ourselves to drift back toward such things, what would we be doing? We would be going against the spirit-inspired counsel of God’s Word, the Bible. By doing this, we would be grieving the holy spirit.
In Ephesians chapter 5, we read Paul’s counsel about avoiding prurient interest in fornication. The apostle also urges fellow believers to avoid shameful conduct and obscene jesting. If we do not want to grieve God’s holy spirit, we ought to bear this in mind when choosing entertainment. Why would we show interest in such things by talking about them, reading about them, and viewing their portrayal on television or elsewhere?
Of course, we could grieve the spirit in other ways. Jehovah’s spirit promotes unity in the congregation, but suppose we were to spread harmful gossip or encourage cliques in the congregation. Would we not be working against the spirit’s leadings toward unity? In a general way, we would be grieving the holy spirit, like those who caused divisions in the congregation in Corinth. (1 Corinthians 1:10; 3:1-4, 16, 17) We would also be grieving the spirit if we deliberately undermined respect for spirit-appointed men in
