Rejoice always, (17) pray without ceasing, (18) in everything give thanks for this is the will of God in Jesus Christ for you. (19) Do not quench the Spirit. (20) Do not despise prophecies. (21) Test all things; hold fast what is good. (22) Abstain from every form of evil. (23) Now may the God of peace Himself sanctify you completely; and may your whole spirit, soul, and body be preserved blameless at the coming of our Lord Jesus Christ. (24) He who calls you is faithful, who also will do it.

The first letter to the Thessalonians was written by the apostle Paul. Our verses today contain distinct exhortations for Christian behavior, written by Paul to new believers many of whom were suffering persecution because of their faith.

Paul commands us to rejoice always; not with that which the world gives, not that which nature inspires but that joy which comes from God that nothing can overcome or destroy. Rejoicing is intentional – a conscious attitude of contentment, hope and happiness. If God’s joy disappears or we cannot pray we can be sure something is wrong and we are out of fellowship from God.
We are told to pray without ceasing. Keep asking, seeking and knocking.
A grateful heart pleases God in sad days as well as glad. Gratitude and holiness go together. We develop a habit of rejoicing by a daily focus on the riches of God in Christ; walk in the spirit, not the flesh.
The unsaved may resist the Spirit but it’s only in the believer that the Spirit is quenched because it is only in the believer that the Spirit dwells. We quench the Spirit when we trust in our rituals and routines rather than the Holy Spirit. We hinder the working of the Spirit when we tolerate any known sin.
We are not to dismiss the prophets but to be ready to recognize messages based on the word of God.
We are to test or evaluate different teachings and accept that which agrees with Scripture – and to reject all else. And we are to abstain from all appearance of evil.

Justification is absolutely complete from the moment we believe. Christ is our sanctification and we are complete in Him. To sanctify means to set apart from worldly things and we should always be aware that we cannot do life on our own. Holy living will be our habit when trusting in God is our habit.