Please read Competing Prayers, by Alistair Begg, at One Place.
"O death! Why do you touch the tree beneath whose spreading branches weariness finds rest? Why do you snatch away the excellent of the earth, in whom is all our delight? If you must use your axe, use it upon the trees that yield no fruit; then you may be thanked. But why will you chop down the best trees? Hold your axe, and spare the righteous.
"But no, it must not be; death strikes the best of our friends: the most generous, the most prayerful, the most holy, the most devoted must die. And why? It is through Jesus' prevailing prayer:
"Father, I desire that they also, whom You have given Me, be with Me where I am, so that they may see My glory which You have given Me, for You loved Me before the foundation of the world." John 17:24
"Lord, You shall have them. By faith we let them go."