Francis Bacon wrote just over a hundred essays between 1597 and 1625), many of which discuss how man should handle himself in difficult situations--in this case, how one should view adversity and how one should act in the face of adversity.
According to Bacon, who quotes the Roman philosopher Seneca:
The good things, that belong to prosperity, are to be wished; but the good things, that belong to adversity, are to be admired.
By this Bacon means that prosperity is easy to handle, but because adversity is so hard, anyone who can manage to live through adversity is to be admired. Bacon refers to another statement of Seneca's: true greatness in a human being is to have all the weaknesses of the human, but the fortitude (strength, sureness) of God.
Essentially, throughout the essay, Bacon contrasts prosperity, which leads to easy decisions about how to live one's life, and adversity, which requires a strength of moral character that prosperity does not. For example, he compares Hercules, who sailed in a strong vessel to free Prometheus from his chains, to the Christian "that sailed in the frail bark of the flesh, through the waves of the world." In other words, Hercules was sailing in relative prosperity, which made his voyage easy; the Christian, on the other hand, faces the world in a frail body--in Bacon's view, the Christian has more fortitude--strength and bravery--because he must take on the world with the adversity created by his frail body.
In a Christian context, according to Bacon, prosperity leads to comfort and therefore to vices, but adversity, because it requires moral strength, leads to the creation of virtue. In fact, Bacon says that "virtue is like precious odors, most fragrant when they are . . . crushed," by which he means that virtues become stronger when they are "crushed" by adversity.