The minute we die our bodies start to decay. According to scientists, a year after we die all that is left of our bodies is our bones. Embalming can slow the process so that a proper funeral can be held but the decay of our bodies is inevitable.
Scripture tells us this is because of sin. God tells Adam after he and Eve fell into sin:
“By the sweat of your face you shall eat bread, till you return to the ground, for out of it you were taken;
for you are dust, and to dust you shall return.” (Genesis 3:19)
Ash Wednesday, the first day of the season of Lent, is the day set aside in the church calendar to remind ourselves that we will return to dust because of our sins.
Isaiah 40:6–8 puts it this way:
“A voice says, “Cry!” And I said, “What shall I cry?” All flesh is grass, and all its beauty is like the flower of the field.
 The grass withers, the flower fades when the breath of the LORD blows on it; surely the people are grass.
 The grass withers, the flower fades, but the word of our God will stand forever. (ESV)
So when it was discovered recently that the body of a nun who had died four years ago in Missouri had not decayed it attracted a lot of attention. Some are calling it a miracle.
Based on what the Apostle Peter says in the Day of Pentecost, many believe that if a person’s body does not decay it is an indication that the person was a very holy person:
“For you will not abandon my soul to Hades or let your Holy One see corruption.” (Acts 2:27)
But Peter was quoting a prophecy from King David about Jesus, not speaking about holy people in general. Whether a nun’s body in Missouri decays or not is not as important as knowing that in Jesus all things will be restored:
“So is it with the resurrection of the dead. What is sown is perishable; what is raised is imperishable.  It is sown in dishonor; it is raised in glory. It is sown in weakness; it is raised in power.  It is sown a natural body; it is raised a spiritual body. If there is a natural body, there is also a spiritual body.  Thus it is written, “The first man Adam became a living being”; the last Adam became a life-giving spirit.  But it is not the spiritual that is first but the natural, and then the spiritual.  The first man was from the earth, a man of dust; the second man is from heaven.  As was the man of dust, so also are those who are of the dust, and as is the man of heaven, so also are those who are of heaven.  Just as we have borne the image of the man of dust, we shall also bear the image of the man of heaven.” (I Corinthians 15:42-49)
So, through faith in Jesus, even though we die, we will rise, body and soul to imperishable life in heaven.
Jesus said to her, “I am the resurrection and the life. Whoever believes in me, though he die, yet shall he live,  and everyone who lives and believes in me shall never die. Do you believe this?”  She said to him, “Yes, Lord; I believe that you are the Christ, the Son of God, who is coming into the world.” (John 11:25-26)
“For I know that my Redeemer lives, and at the last he will stand upon the earth.
 And after my skin has been thus destroyed, yet in my flesh I shall see God,
 whom I shall see for myself, and my eyes shall behold, and not another.
My heart faints within me! (Job 19:25-27)