As Christians we are to grow in the faith, live a life that honors God and show forth His holiness working in our livs; we are to love one another, and to comfort one another with the words of hope concerning the Lord’s return.
In the Christian life growth occurs as one is obedient to the principles of God’s Word. To participate in the demeaning, immoral activities of the world system, as a Christian is to rob one’s self of spiritual growth.
Verses one through twelve have to do with a Christians growth. The same man who [under the inspiration of the Holy Spirit] wrote about our freedom [liberty] in Christ, also writes about abstaining from certain activities. Paul is here concerned abou their sanctification, as he would be ours as well. Our being separate, peculiar, different, is to be a distinction even others can notice. In the first chapter verse four, Paul recognized some individuals as being, “The elect of God”. He knew this by the way they lived, and so did “those who are outside”. Their lives were different, certainly in the way they loved (v. 9). There had been changes wrought in their lives; dramatic changes.
The growing Christian is changing daily. Each day he is more like Jesus than the day before, at least that is how it should be. Yielding to the Father; trusting Him with lifes ups and downs, ministering to others needs, never taking advantage of a brother’s weakness(es) to profit himself. Paul warned that, “The Lord is the avenger of all such” (v. 6).
The people at Thessalonica were concerned about their deceased loved ones, who had died in Christ and verses thirteen through eighteen handle that teaching for us. These fit together real well, because a clean and holy life is the only one God will accept into His Kingdom (Psalm 15). We can only live that life in the power of God’s Spirit, and that through faith in the shed blood of Jesus and His finished work. Our redemption finished when the bodies of the Saints shall all be redeemed by Jesus’s coming in the clouds.

Furthermore then we beseech you, brethren, and exhort you by the Lord Jesus, that as ye have received of us how ye ought to walk and to please God, so ye would abound more and more. 2 For ye know what commandments we gave you by the Lord Jesus. vv. 1-2.

Pleasing God, to even professing Christians is often as difficult as walking a narrow pole across the Grand Canyon. It is not that difficult if one is born-again through Christ Jesus. It is a matter of trusting Him to carry you across the canyon.
This leader (Paul) is calling on them to get nearer to Jesus. The life of a Christian is to be lived as an example to others, keeping the commandments, and being pleasing to God. We are not being saved by keeping the commandments, but being saved we keep the commandments.

For this is the will of God, even your sanctification, that ye should abstain from fornication: that every one of you should know how to possess his vessel in sanctification and honour; not in the lust of concupiscence, even as the Gentiles which know not God: that no man go beyond and defraud his brother in any matter: because that the Lord is the avenger of all such, as we also have forewarned you and testified. vv. 3-6.

Knowing the will of God is at times difficult, especially when we get confused about what is important, confused about what should take top priority in life, and when we are not giving to God what we already know to be His will.
The Word of God tells us God’s will for our lives. If we shun His Word why should we expect Him to show us His will in what boy or girl to marry, which house to buy, or which job to take? If we keep His commandments, because we love Him (Not for salvation), we will know His will, and can then, seek His counsel in every day questions.
There must be holiness in the Christian’s life. “This is the will of God”. It means abstaining from all forms of immorality, having self-control and knowing how to treat your spouse, caring for the weaker brother, and even the stronger. It means loving the Lord Jesus. Paul warns that the Lord is the one who avenges in such cases.

For God hath not called us unto uncleanness, but unto holiness. He therefore that despiseth, despiseth not man, but God, who hath also given unto us His Holy Spirit. vv. 7-8.

God has called us to be holy. Holiness is being clean for this Person of purity [the Holy Spirit] to live in and use for God’s glory. Jesus said, “He who believes in Me, as the Scripture has said, out of his heart [belly] shall flow rivers of living water” (John 7:38). How can the water be clean if the vessel is dirty? If you are living in sin who is going to believe you when you say, “Jesus can set you free. Look what He has done for me!”? No one will. You can count on it.
To reject is to wreak havoc upon your life. These are God’s words, God’s instructions to His people. If you will not believe His Word at this point you do not believe it at any place, therefore, you are lost and condemned to the fires of Hell.

But as touching brotherly love ye need not that I write unto you: for ye yourselves are taught of God to love one another. And indeed ye do it toward all the brethren which are in all Macedonia: but we beseech you, brethren, that ye increase more and more; and that ye study to be quiet, and to do your own business, and to work with your own hands, as we commanded you; that ye may walk honestly toward them that are without, and that ye may have lack of nothing. vv. 9-12.

The lack of love was not a problem, yet Paul says, “We urge you…increase more and more”. In what? In love. You cannot love, with God’s love, too much.
It is because of love we are to work, and not meddle in other’s lives, and to take care of our own business. Out of love our work life is to be just as good a witness to the condemned world as our faithfulness to attend worship. Others are watching. Those who do these things will live a life of joy, peace, and lack no good thing.

But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope. For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with Him. for this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep.  For the Lord Himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. vv. 13-17.

These verses speak of the “Blessed hope…”, which Paul writes of in Titus 2:13, and says, “Looking for that blessed hope…”. Paul was looking for it then, why are we not “Looking for that blessed hope” today?
A proper walk with God is not only conducive as a witness to the condemned, but also in preparation for the coming of Jesus.
The Thessalonian Christians were uncertain about their dead loved ones in Christ. What would become of them? For some reason the church – or at least many of them – were afraid that their loved ones who had died in Jesus would miss “the victories and glories” of Jesus’s return. It is made clear that, that just is not true. The word sleep is used in reference to the body, not the soul and/or spirit. “To be absent from the body is to be present with the Lord” (2 Corinthians 5:8).
There was some ignorance concerning those who “Slept”. Some, evidently thinking it was over for the dead; no hope, no glory, no eternal life.
Verse fourteen clarifies that those who are dead will be with Him [Jesus] when He comes for His Church. Their spirit and soul will be united with a new resurrected body. It will be a body like that of Jesus’s resurrected body.
Verses fifteen and sixteen make it clear the living believers will not go before or without the dead in Christ. The dead will rise first (v. 17); then, the living will rise with them to meet the Lord Jesus; the Lamb of God; the King of kings, and Lord of lords.

Wherefore comfort one another with these words. v. 18.

We need this kind of comfort. Knowing Jesus is coming back should cause us to be comforted. Notice though who is to be the comforter – we are to one another; “With these words…”. There is comfort in reading the Scriptures of prophecy in the prophets, Moses, the apostle John, and in Matthew chapter 13, and 24-25. These should be encouraging words for the Christian, and real motivation to warn those who are condemned by sin.

In conclusion of these verses, our lives should be lived for Jesus. This is certainly a world in desparate need, but the child of God can live in comfort and peace by taking heed to God’s Word. We need each others encouragement if we are to live in this “Modern World”. We need to be encouraged to abstain from things that displease God. We need to be encouraged to live clean lives. We need to be encouraged about the return of Jesus.
Not only the people of the world, but the earth itself is in a state of madness. Earthquakes where they have never been before – in recorded history. The weather odd and unseasonal, breaking into storms that cause multi-billions of dollars of damage; thousands and thousands of peoples lives destroyed by death and destruction. Today, in 2020 a pestilence [COVID-19] that is plaguing the world with hundreds of thousands dead from it.
The Christian can live in peace. She/He can live, because they know God has their life in His hands, and we encourage one another to this extent.
THE WALK WHICH PLEASES GOD is when we walk with Jesus Christ our sin-bearer, Redeemer, and expecting His soon return. “Even so, come Lord Jesus”.