What does 1 Thessalonians 5:19 mean?

Fire is often used in reference to the Holy Spirit (Isaiah 4:4; Matthew 3:11; Acts 2:3–4). Paul warns his readers against dousing or smothering the ministry of the Holy Spirit, who warms the heart to love God and others. The Spirit inspires believers to serve God faithfully, to worship, to pray, and to encourage others. He ignites believers' hearts with zeal to win unbelievers to Christ. Resisting the Spirit's ministry leads to a lukewarm attitude and to the loss of reward (Revelation 3:14–22).

Before the flood that swept away everyone except Noah and his family, humanity was utterly corrupt and had no regard for God. Genesis 6:5 tells us, "The LORD saw that the wickedness of man was great in the earth, and that every intention of the thoughts of his heart was only evil continually." It was this depraved thinking and acting that caused God to announce a limit to His patience with man's earthly antics (Genesis 6:3). By quenching the Spirit, humanity had stirred up God's wrath. It is always best to respond positively to the Spirit's influence!