When Harry Potter found his parents' grave in the last book of the series, he discovered an inscription on it: "The last enemy that shall be destroyed is death." Harry took this quotation to heart, and perhaps it helped him at a crucial moment in his fight against the evil Lord Voldemort.
This quotation originates from Paul's first letter to the Corinthians. He is explaining to them that just as death came into the world through a man—Adam—it would also be destroyed by a man—Jesus. Jesus will return to collect the kingdom for the Father. "For he must reign until he has put all his enemies under his feet. The last enemy to be destroyed is death." (1 Corinthians 15:25–26) Death is the epitome of everything that has gone wrong in God's creation, the results of sin, disobedience, and depravity. When God has eradicated all of the flaws that lead us to death, then He can destroy death itself and we will be returned to the perfect life that God envisioned for us when He created Adam and Eve.
In the end it must be God who defeats death, not us. Still, death will defeat us if we do not trust in the promise. As long as we live in dreadful fear of death, we give it undue power over us. We can't do anything about death right now, and someday it will touch us. That's true. But that's also as it should be. Death is the last enemy to be defeated, so let's not worry about it before it's time. Death will come in the end, and it will be defeated. Why should we be so afraid?
In the meantime, we ought to be focusing on the other enemies, things like sin and and corruption and selfishness. God does give us power to fight those. We can't do anything about death, but we can work towards a healthier life. We can learn to live in joy instead of fear, with hope instead of dread. One day death will come for us, but that will be a day of joy, the day we go to meet God in Paradise. Today we also have a chance for joy if we allow God to help us cast the fear of death and the stain of sin away from us.
The last enemy to be destroyed is death. It will happen, but not right now. Trust in that, and don't be afraid.