1 Thessalonians KJV

Thessalonians is a book on the faith of the saints to take comfort in the fact that God will restore all that is lost. If you are burdened by the loss of a beloved saint, just remember that the Lord promises us that the ones that have gone on to the grave will rise again with the coming of Christ. However, do not take this message the wrong way. We must remember in order to rise with the Lord we must first have been in the Lord and accepted by his grace and mercy. I simply do not want to give false reassurance. This is exactly why we all must come to the knowledge of the reality of hell and everlasting life. Christ is not a joke, He is truth and salvation. Only through Him can a man be saved from the destruction that is to come.
This is why we all must carry the great commision in our hearts to spread the gospel to all mankind. For the gospel is the only way to have assurance from the tragic fate of hell. Likewise, always remember that we are not the final judge, and at the last moment in a man's life God can still be revealed to them and they can receive salvation. This does not mean that we as saints, or anyone for that matter, should live lives contrary to the word of God and expect that the Lord will just forgive you at the last second of your life. That would be a very insecure future. Why leave your salvation up to chance? Instead seek the kingdom first while there is still time. Then, if you receive the grace of God now, you can begin to live a life, a true life, through the power of the Holy Ghost.
Lastly, remember that God is a just God, and that He has all power and authority and knowledge to make the final judgment of a man's heart. He will not fail to do the right thing. With that said, if there is anyone in your life that you grieve that you believe had no relationship with the Lord then also take comfort in the fact that the Lord proclaims that when He comes, He will wipe away all the tears, then we will be with HIm in glory (Rev. 21:4, Isaiah 25:8). Wait for the Lord, and He will make all well with you. Amen.