William MacDonald emphasizes the seriousness of defiling the temple of God, which refers to the local assembly of believers. He explains that Paul warns against those who destroy the unity and holiness of the church, as such actions lead to God's judgment. The sermon highlights the dangers of gossip, factionalism, and personal conflicts within the church, which can lead to its downfall. MacDonald reminds the congregation that both individual believers and the collective assembly are sacred, and tampering with them is a grave offense. Ultimately, he calls for unity and purity within the church to honor its divine purpose.

“If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.” (1 Cor. 3:17) In this verse, the temple of God refers to the local assembly. Paul is not speaking to individual Christians but to believers collectively when he says “which temple ye (plural) are.” The saints in Corinth comprised a temple of God. It is also true, of course, that individual believers are a temple of the Holy Spirit. The Apostle brings this out in 1 Corinthians 6:19: “What? know ye not that your body is the temple of the Holy Ghost which is in you, which ye have of God, and ye are not your own?” The Holy Spirit of God dwells in the body of every child of God. But in our text for today it is the assembly that is in view. Paul is saying that if any man destroys the assembly, God will destroy him. It is the same word that is translated “defile” and “destroy” in this verse. It is used of marring a local church by leading it away from that condition of holiness of life and purity of doctrine in which it should abide, and of God’s retributive destruction of the offender who is guilty of this sin” (W. E. Vine). So our verse warns us that it is a serious thing to tamper with a local fellowship. In fact, it is a form of self-destruction. Yet how diffident people often are in this very area. Here is a man who doesn’t get his own way in the assembly. Or he becomes involved in a violent personality clash with some other brother. Rather than make things right in a Scriptural manner, he lines up people to take his side and forms a faction in the church. Things go from bad to worse and soon there is an open split. Or perhaps it is a carnal sister who carries on a campaign of gossip and back-biting against someone else. Her slanderous tongue lashes out until the church is filled with bitterness and strife. She will not stop until a once-prosperous assembly lies in ruins. People like this are playing a perilous game. They cannot get away with it. The Great God of the universe is committed to wreck those who wreck His assembly. Let all who are inclined to faction beware!