In the work, suffering cleanses, as our sages said, “I place over you a king such as Haman, who will reform you against your will” (Berachot 5a). In other words, the nature of the will to receive is that it wants to enjoy life.
When a person receives into his heart a part of the soul of Kedusha [holiness], and the soul wants to be a giver, and the will to receive does not give it the required forces, then the will to receive itself takes no pleasure in life, since the desire to bestow does not let it rest. Each day, it makes it see that if he lives like a beast, this is not a life, when his only needs are worldly lusts.
By this he becomes fed up with life and feels only suffering in life because in everything he does and wants to enjoy, the soul of Kedusha does not give him satisfaction in this life. Finally, the will to receive itself says, “I see I have no choice but to obey the desire to bestow, for otherwise I will have no rest. This is called “who will reform you against your will.”