The Poet says his poem depicts a man favored by Fortune and admired by all, but also comments that Fortune is fickle, and can change suddenly. And in that situation, those who admired and flattered the successful man would not step to his aid. For the moment Timon is the man admired by all, and several will admit that they owe Timon everything (as Lucilius does). In the event of a change of fortune, the Poet has predicted correctly--Timon's friends will abandon him. But the Poet depicts this as a fault of Fortune, whereas for Timon it comes to be a fault of his fickle friends.