Once, when a wealthy chassid came to the Rebbe [Rashab], the Rebbe mentioned the Talmudic passage: "The world is a turning wheel," and added that although a wheel is round, there is still a top and a bottom.

The Rebbe continued: In the central garden of Vienna there is a large Ferris wheel that stands above the ground. On its sides hang wagons made of glass and decorated with metal trimmings so that the one riding is able to see from all angles. When the wagon is lifted off the ground, he is also lifted. And when he reaches the highest point, he is able to see very far. The wheel turns and the wagons begin to descend, and in this way the turning of the wheel brings about the ascent and descent of the wagons.

There is a time when the person is on top, and there is a time when the person is on the bottom.

The nature of man is that when he is on top, he feels uplifted and laughs out of goodness, and when he is, G-d forbid, on the bottom, he is saddened and weeps out of bitterness and a heavy heart.

However, both of these people are fools.

The one on the bottom who is weeping out of sadness must be challenged: Why are you crying? It is only a wheel, and a wheel's nature is to turn. G-d will help and you will be helped.

And the one on top of the wheel who feels exalted must also be challenged: Why are you so excited? It is only a wheel and a wheel's nature is to turn.

Sefer HaSichos 5696, p. 32;

Igros Kodesh of the Rebbe Rayatz, vol. 5, p. 117