The line that you mention comes from Mao Zedong, the leader of the Chinese communists during and after their struggle to take control of China. Mao uses this phrase as part of a statement of the idea that revolution must necessarily be violent and uncomfortable for society.
In his "Report on the Peasant Movement in Hunan," written in 1927, Mao argues against the idea that he and his movement are going too far and being too radical. He counters with the phrase that you have cited here and goes on to argue that there is no way to overcome the entrenched inequalities and injustices in a society without being revolutionary, radical, and violent.
Mao Zedong wrote the following words in his essay, “Report on an Investigation of the Peasant Movement in Hunan”. In Mao’s eyes, a revolution could not be gentle or temperate in nature - violence was required for a revolution to succeed since a class, that had been so deeply entrenched, could not be overthrown so easily. To fully root out the landlord class, revolutionary fervour was needed.