Answer: Karl Marx
Explanation:
Vera Ivanovna Zasulich (1851 – 1919) was a Russian Menshevik writer.
Zasulich and Karl Marx had an exchange of letters in 1881 that would later be published in Russia in 1924 (Arkhiv K. Marksa i. F. Engels, Volume 1). These letters, where the quoted phrase can be found, showed the intellectual process behind Marx´s theory and his ideas about revolution.