In these words observe,

I.The apostle tells the Thessalonians it was needless or useless to enquire about the particular time of Christ's coming: Of the times and seasons you need not that I write unto you, Th1 5:1. The thing is certain that Christ will come, and there is a certain time appointed for his coming; but there was no need that the apostle should write about this, and therefore he had no revelation given him; nor should they or we enquire into this secret, which the Father has reserved in his own power. Of that day and hour knoweth no man. Christ himself did not reveal this while upon earth; it was not in his commission as the great prophet of the church: nor did he reveal this to his apostles; there was no need of this. There are times and seasons for us to do our work in: these it is our duty and interest to know and observe; but the time and season when we must give up our account we know not, nor is it needful that we should know them. Note, There are many things which our vain curiosity desires to know which there is no necessity at all of our knowing, nor would our knowledge of them do us good.

II.He tells them that the coming of Christ would be sudden, and a great surprise to most men, Th1 5:2. And this is what they knew perfectly, or might know, because our Lord himself had so said: In such an hour as you think not, the Son of man cometh, Mat 24:44. So Mar 13:35, Mar 13:36, Watch you therefore, for you know not when the master of the house cometh; lest, coming suddenly, he find you sleeping. And no doubt the apostle had told them, as of the coming of Christ, so also of his coming suddenly, which is the meaning of his coming as a thief in the night, Rev 16:15. As the thief usually cometh in the dead time of the night, when he is least expected, such a surprise will the day of the Lord be; so sudden and surprising will be his appearance. The knowledge of this will be more useful than to know the exact time, because this should awaken us to stand upon our watch, that we may be ready whenever he cometh.

III.He tells them how terrible Christ's coming would be to the ungodly, Th1 5:3. It will be to their destruction in that day of the Lord. The righteous God will bring ruin upon his and his people's enemies; and this their destruction, as it will be total and final, so, 1. It will be sudden. It will overtake them, and fall upon them, in the midst of their carnal security and jollity, when they say in their hearts, Peace and safety, when they dream of felicity and please themselves with vain amusements of their fancies or their senses, and think not of it, - as travail cometh upon a woman with child, at the set time indeed, but not perhaps just then expected, nor greatly feared. 2. It will be unavoidable destruction too: They shall not escape; they shall in no wise escape. There will be no means possible for them to avoid the terror nor the punishment of that day. There will be no place where the workers of iniquity shall be able to hide themselves, no shelter from the storm, nor shadow from the burning heat that shall consume the wicked.

IV.He tells them how comfortable this day will be to the righteous, Th1 5:4, Th1 5:5. Here observe, 1. Their character and privilege. They are not in darkness; they are the children of the light, etc. This was the happy condition of the Thessalonians as it is of all true Christians. They were not in a state of sin and ignorance as the heathen world. They were some time darkness, but were made light in the Lord. They were favoured with the divine revelation of things that are unseen and eternal, particularly concerning the coming of Christ, and the consequences thereof. They were the children of the day, for the day-star had risen upon them; yea, the Sun of righteousness had arisen on them with healing under his wings. They were no longer under the darkness of heathenism, nor under the shadows of the law, but under the gospel, which brings life and immortality to light. Ti2 1:10. 2. Their great advantage on this account: that that day should not overtake them as a thief, Th1 5:4. It was at least their own fault if they were surprised by that day. They had fair warning, and sufficient helps to provide against that day, and might hope to stand with comfort and confidence before the Son of man. This would be a time of refreshing to them from the presence of the Lord, who to those that look for him will appear without sin unto their salvation, and will come to them as a friend in the day, not as a thief in the night.

Ye are all the children of light - Ye are children of God, and enjoy both his light and life. Ye are Christians - ye belong to him who has brought life and immortality to light by his Gospel. This dispensation, under which ye are, has illustrated all the preceding dispensations; in its light all is become luminous; and ye, who walked formerly in heathen ignorance, or in the darkness of Jewish prejudices, are now light in the Lord, because ye have believed in him who is the light to lighten the Gentiles, and the glory and splendor of his people Israel.

We are not of the night, nor of darkness - Our actions are such as we are not afraid to expose to the fullest and clearest light. Sinners hate the light; they are enemies to knowledge; they love darkness; they will not receive instructions; and their deeds are such as cannot bear the light.

Ye are all children of light,.... Or enlightened persons, whose understandings were enlightened by the spirit of God, to see their lost state by nature, the exceeding sinfulness of sin, the insufficiency of their righteousness to justify them before God, the fulness, suitableness, and excellency of Christ's righteousness, the way of salvation by Christ, and that it is all of grace from first to last; to understand in some measure the Scriptures of truth, and the mysteries of the Gospel; to have knowledge of some things that are yet to be done on earth, as the bringing in of the fulness of the Gentiles, the conversion of the Jews, the destruction of antichrist, the second coming of Christ, the resurrection of the dead, the change of living saints, and the rapture of both up into the air to meet Christ, the burning of the world, and the new heavens and new earth, where Christ and his saints will dwell; as also to have some glimpse of the heavenly glory, of the unseen joys, and invisible realities of the other world: and this the apostle says of them all, in a judgment of charity, as being under a profession of the grace of God, and in a church state, and nothing appearing against them why such a character did not belong to them:

and the children of the day; of the Gospel day, in distinction from the night of Jewish darkness; and of the day of grace which was come upon their souls, in opposition to the night of ignorance and infidelity, which was past; and of the everlasting day of glory, being heirs of, and having a right unto, and a meetness for the inheritance of the saints in light:

we are not of the night, nor of darkness; that is not the children of darkness, as the Syriac and Arabic versions read; and the former changes the person, and reads, "ye are not the children of the night", &c. of the night of the legal dispensation, or of Gentile ignorance; or of a state of natural darkness, in unregeneracy and was no need to write unto them concerning the time and season of Christ's coming, and lays a foundation for the following exhortations.

The oldest manuscripts read, "FOR ye are all," &c. Ye have no reason for fear, or for being taken by surprise, by the coming of the day of the Lord: "For ye are all sons (so the Greek) of light and sons of day"; a Hebrew idiom, implying that as sons resemble their fathers, so you are in character light (intellectually and morally illuminated in a spiritual point of view), Luk 16:8; Joh 12:36.

are not of--that is, belong not to night nor darkness. The change of person from "ye" to "we" implies this: Ye are sons of light because ye are Christians; and we, Christians, are not of night nor darkness.