Paul employs a military metaphor of a sentry on duty. He writes of "the breastplate of faith and love, and as a helmet the hope of salvation," soldiering gear. The alert and self-controlled sentry, vigilant for signs of the enemy, is entrusted with the safety of those within his camp. Normally, he is neither lackadaisical nor wildly excitable. His armor and weapons grant him a measure of control and ability when the need arises.
Similarly, a Christian should become neither lackadaisical nor wildly excited about the time of the end without the controlling factors of faith, hope, and love. There is nothing wrong with speculating about the time of Christ's return. Speculating is a natural result of watching and evaluating the times. However, since even Christ did not know the time of His return, we would be very arrogant to think that we might have had it revealed to us. In reality, if someone claims to know when Christ is coming, it is nothing short of blasphemy! That person is calling God a liar! Jesus Christ says nobody knows, not even the Son (Mark 13:32), and the implication is that the Father will not tell the Son until it is just about time for Him to return.
John W. Ritenbaugh
The World, the Church, and Laodiceanism
The helmet protects the head, the part of the body most vital to quality of life. It is the thinking part where choices and judgments are made, where attitudes reside and surge forth in conduct. It is the part that holds knowledge, understanding, wisdom, and memories of life's experiences, that determines the kind of life we lead. It is that part where Satan aims most of his fiery darts.
In this metaphor, hope is not an offensive weapon but a defense; it is a motivator to protect us from losing sight of the glorious end of God's purpose. Why? The only thing that can really defeat and destroy us is for us to give up. Jesus says in His Olivet prophecy, "But he who endures to the end shall be saved" (Matthew 24:13). Hope's fruit is not just an optimistic and positive outlook but also the drive to persevere, to endure come what may, to propel one forward. Only the hopeful will do this. The hopeless will give up.
So powerful is hope's action that Paul says in Romans 8:24-25 that we are saved by it! "For we are saved in this hope, but hope that is seen is not hope; for why does one still hope for what he sees? But if we hope for what we do not see, we eagerly wait for it with perseverance." This in no way conflicts with his declaration in Ephesians 2:8 that we are "saved by grace through faith," because both faith and hope are necessary for salvation. Faith primarily operates in the present as visible evidence of things hoped for but not yet seen. Hope, though it is also operating in the present, primarily does so with reference to the future. Paul then says that, if a person has hope, he is motivated to wait patiently for what he hopes to see. The hopeful are motivated to endure whatever it takes to receive what they hope for.
John W. Ritenbaugh
The Elements of Motivation (Part Three): Hope
Like us, the return of Christ was much on the minds of first-century Christians, yet Paul tells them he felt no need to write concerning its timing. Why? Because they should have known that the Day of the Lord will come like a thief in the night. There was no point in Paul trying to outline it all, as it will happen at a time that nobody can anticipate.
However, he writes something that seems contradictory in verse 4: Since they are not in darkness, that Day should not "overtake [them] as a thief." What is actually meant is that the day of God's wrath would not possess them—literally, "take them over." God's wrath would not swallow them up, or the destruction of that Day does not need to have power over them. He does not mean that it would not surprise them, but as a parallel verse clarifies, "For God has not appointed us to wrath" (verse 9), even though they will be surprised.
Verse 6 contains the same admonition seen elsewhere to be awake, to be sober, and to watch. Though we are not appointed to wrath, other verses show that we can certainly still incur it if we are not taking heed to ourselves (see Hebrews 10:26-31). So we are instructed to watch—to be vigilant about our spiritual state, to have continuous and wakeful concern over fulfilling our part of the covenant, to be on guard against spiritual dangers, spiritual drowsiness, and deception. Those who do these things, along with praying always, will be accounted worthy to escape the wrath. Simply watching down the road for a sign of the Master's return really does not prepare us for anything at all.
David C. Grabbe
'As a Thief in the Night'
Other Forerunner Commentary entries containing 1 Thessalonians 5:8:
2 Thessalonians 2:1-9