But we do not want you to be uninformed, brethren, about those who are asleep, that you may not grieve, as do the rest who have no hope. For if we believe that Jesus died and rose again, even so God will bring with Him those who have fallen asleep in Jesus.1 Thessalonians 4:13-14
But when this perishable will have put on the imperishable, and this mortal will have put on immortality, then will come about the saying that is written," Death is swallowed up in victory."
"O Death, where is your victory? O Death, where is your sting?"
The sting of death is sin, and the power of sin is the law; but thanks be to God, who gives us the victory through our Lord Jesus Christ. Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, knowing that your toil is not in vain in the Lord.1 Corinthians 15:54-58
Sin is the reason that death is in the world.
Therefore, just as through one man sin entered into the world, and death through sin, and so death spread to all men, because all sinned...
But we have hope in Christ because of His free gift:
But the free gift is not like the transgression. For if by the transgression of the one the many died, much more did the grace of God and the gift by the grace of the one Man, Jesus Christ, about to the many.Romans 5:15
Thanks be to God for His indescribable gift!