"Within the deepest recesses of the human heart is the longing to live
forever.
There is something in us that repulses the cold reality of
death. 
In the perfect world that God created for mankind there were no graveyards because man was not made by his Creator to
suffer death. Death, pain, sorry and sickness was never meant to be part
of the experiences of man.
The Bible teaches that God created us in His
image (And God said, Let us make man in our image, after our likeness: Genesis 1:26).
Since our Creator possess immortality (Who only hath immortality, dwelling in the light which no man can approach unto; whom no man hath seen, nor can see: ... 1 Timothy 6:16),
it was His plan to bestow on us this gift of eternal life.
However, just like other intelligent beings in the universe of God, we
had a choice to make. One of the Creator's special angelic creation
called Lucifer has disobeyed Him and cast a snare on His character of love.
It therefore became
necessary for all intelligent beings in the universe of God to choose
whether they will obey the Creator, God or they will defect to the side
of Lucifer and his host of fallen angels.
Paul made this point clearer when he wrote the following statement in the book of Romans: "For the wages of sin is death" (Romans 6:23).
Beloved, the Bible is clear. We die because of sin. We die because of
our disobedience to the express commandments of God. In fact, sin is
defined in Scripture as the transgression of the law of God (1 John 3:4).
Sin is actually obeying the voice of Satan instead of heeding to the
commandments of God. And as we have noted above, sin brings with it the
painful consequences of sorrow, misery, pain and ultimately death." WhiteThroneMinistries