In the second chapter the Apostles had put their example before the saints, for them to follow; now they beseech the saints and exhort them by the Lord Jesus, that according to that example and teaching, they should walk and please God, and abound more and more in it. They would have them be like Enoch, who walked by faith, realizing death passed for him on the slain lamb, and looking to be translated that he should not see death, and whilst waiting, walking with God, and having this testimony that he pleased God. (Cp. Heb. 11:4-5.)
The young Thessalonian converts knew what commandments the Apostles had given them by the Lord Jesus. It was the will of God, their full sanctification, which is divided in the following verses,
1st, in their being separated from fornication and all evil lusts;
2nd, to holiness; and
3rd, to love one another, which learning practically as we have seen above, their hearts would be established unblameable in sanctification before God and the Father at the coming of the Lord with all His saints.
Fornication was rife in those heathen countries, a common sin; but the saints were to keep their vessels in sanctification and honour, not allowing their passions and lusts to have dominion over them as the heathen who did not know God; much less for any one to overreach his brother in such a matter, for the Lord was the avenger of all such; God had not called them to uncleanness, but to sanctification. It was not despising man, but despising God to do such things, who had given them His holy spirit.
But, 3rd, their sanctification was bound up with brotherly love. We know we have passed from death unto life because we love the brethren, and this carried out would be practical separation from the world. In fact it was to own the Father in contrast with the world. This was positive sanctification, they were taught of God to love one another, and indeed all the brethren in Macedonia (cp. 3:12,) but he besought them that they might increase more and more, and to do good and study to be quiet and to do their own business, and to work with their own hands (as the Apostles commanded them) that they might walk with honesty towards them that were without, and that they might have lack of nothing.
The coming of the Lord is now brought before the young saints to comfort them in connection with their departed relatives (1 Thess. 4:13-18), and in connection with this the two stages of it are distinctly brought out, 1st, to illustrate how the Lord will bring back with him to His kingdom those that have departed before, and 2nd, ch. 5, to show the saints full salvation from the day of the Lord—the Day of Judgment—to the world (ch. 5:1-11).
The Thessalonian believers had evidently but an indistinct notion of the Lord’s coming. Paul and his helpers, as I have shown before, had left them at a very early stage, having given them the general hope of the Lord’s coming without detail. Some of their brethren had in the mean time died. What had become of them? Would they partake of the blessings of the coming of the Lord? These were some of the questions that would arise in the young believers minds. They were taught about the Lord’s coming back to take the kingdom. Would their departed brethren lose their reward? The Apostle now writes to comfort them and gives them full instruction. He would not have them ignorant concerning those that were asleep, that they might not sorrow as those that had no hope of seeing them again; for if they believed that Jesus died and rose again, even so them also that slept in Jesus would God bring with Him, when He returned to set up His kingdom over the earth.
But how return with Him, if they had died? The following verses are a parenthesis to show how this would take place. He said this to them by the word of the Lord, it was a revelation to him that, they which were alive and remained on the earth, at the time of the Lord’s coming should not go before those that were asleep; for the Lord Himself would descend from heaven with a shout, with the voice of the archangel and with the trump of God, and the dead in Christ should rise first; then those that were alive, and remained on the earth at this time, would be caught up together with them to meet the Lord in the air, and so should dead and living be together for ever with the Lord. They would be thus all translated to the glory first, and then return together with the Lord when He came to set up His kingdom on earth. Thus instead of sorrowing, they were to comfort one another in this hope. They would rejoin one another in that day, yea the dead ones would be first to rise.