47 And, indeed, death was no part of man's nature, but became natural; for God did not institute death at first, but gave it as a remedy. Let us then take heed that it do not seem to be the opposite. For if death is a good, why is it written that “God made not death, but by the malice of men death entered into the world”? For of a truth death was no necessary part of the divine operation, since for those who were placed in paradise a continual succession of all good things streamed forth; but because of transgression the life of man, condemned to lengthened labour, began to be wretched with intolerable groaning; so that it was fitting that an end should be set to the evils, and that death should restore what life had lost. For immortality, unless grace breathed upon it, would be rather a burden than an advantage.
Source: On the Death of Satyrus (New Advent)