Does “Him God will destroy” mean physical death or loss of salvation? How will God destroy a Christian in that matter?
I believe the portion you are referring to is found in 1 Corinthians 3:16-17, “Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you? If any man defile the temple of God, HIM SHALL GOD DESTROY; for the temple of God is holy, which temple ye are.”
The Apostle Paul wrote previously in this chapter of how the believers in Christ Jesus are God’s building, himself as a wise master builder, and of Christ as the only foundation. He now proceeds to explain to this Corinthian church, and all the members of the church, that they being unified together as the one body of Christ, were the temple of God…the dwelling place for God in the world. Notice that it is not that all believers are temples, but we form ONE TEMPLE for the habitation of God. We read in 1 Peter 2:5, “Ye also, as lively stones, are built up A SPIRITUAL HOUSE, an holy priesthood, to offer up spiritual sacrifices, acceptable to God by Jesus Christ.”
We are told that “the Spirit of God dwelleth in you.” All individual believers are indwelt with the Holy Spirit as we read in Ephesians 1:13, “In whom ye also trusted, after that ye heard the word of truth, the gospel of your salvation: in whom also after that ye believed, ye were sealed with that holy Spirit of promise.” Yet, we see here that we are indwelt by the Holy Spirit corporately. As the temple of God, we are to be “Endeavouring to keep the unity of the Spirit in the bond of peace.” (Ephesians 4:3).
Let’s now look at the warning that you asked about. 1 Corinthians 3:17 says, “If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.” How can one defile the temple of God, and in what way will God destroy him? In other translations, the word ‘defile’ is given as corrupt, destroy, ruin, and vandalize. We can see the thought here is the opposite of what we read in Acts 20:32, “And now, brethren, I commend you to God, and to the word of his grace, which is able to BUILD YOU UP, and to give you an inheritance among all them which are sanctified.” Instead of building up, the false teacher will seek to defile or destroy the temple of God.
It is obvious that these harmful ones are FALSE TEACHERS, and thus not true believers on the Lord Jesus Christ. The Bible warns us against such people who, “Having a form of godliness, but denying the power thereof: from such turn away. For of this sort are they which creep into houses, and lead captive silly women laden with sins, led away with divers lusts, Ever learning, and never able to come to the knowledge of the truth.” (2 Timothy 3:5-7). We must be aware of these types of people. We must be familiar with the Word of God so that we can stop these people and not allow their corrupting influences in our midst. Perhaps the Lord may destroy them with physical death, but because of their rejection of the truth, they will definitely face eternal judgement from God.
One final thought. True believers on the Lord Jesus Christ can never lose their salvation (John 3:16, John 10:28, Romans 8:38-39, etc.), so we know this warning does not pertain to true believers, only to those who claim to believe but seek to lead God’s people away from His truths. (CC) (632.2)